WorldWideScience

Sample records for polarized light input

  1. Polarimetry with azimuthally polarized light

    Science.gov (United States)

    de Sande, Juan Carlos González; Piquero, Gemma; Santarsiero, Massimo

    2018-03-01

    Nonuniformly polarized light can be used for Mueller polarimetry of homogeneous linear samples. In this work, a set up based on using azimuthally polarized input light and a modified commercial light polarimeter is proposed and developed. With this set up, a Mueller submatrix of a sample can be obtained by measuring the Stokes parameters at only three different positions across the output beam section. Symmetry constraints for linear deterministic samples allow the complete Mueller matrix to be deduced for this kind of specimens. The experimental results obtained for phase plates and for a linear polarizer confirm the validity of the proposed method.

  2. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  3. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  4. Create a Polarized Light Show.

    Science.gov (United States)

    Conrad, William H.

    1992-01-01

    Presents a lesson that introduces students to polarized light using a problem-solving approach. After illustrating the concept using a slinky and poster board with a vertical slot, students solve the problem of creating a polarized light show using Polya's problem-solving methods. (MDH)

  5. POLARIZED LIGHT IN PHYSIOTHERAPY

    Directory of Open Access Journals (Sweden)

    L. D. Tondiy

    2015-12-01

    Full Text Available The data on polarized light (PS - a new promising treatment, rehabilitation and prevention, which took its deserved place among the known therapeutic physical factors and may even compete with laser radiation of low and LED therapy. It is reflected the significant contribution of domestic scientists in the study of aircraft action on the body, its introduction in the treatment, rehabilitation and prevention of grippe, ARI. These action's mechanisms of the aircraft on the electro-physiological processes in the body that have the leading role in the regulation of its life. The new moment in the study of aircraft on the body is the evidence of its positive impact on the mechanisms of self body - its different units: the disease's banning - a revitalization of the stress-protective, stress-limiting system antioxidial, detoxification and other protection systems, the formation by the body antiviral and antimicrobial specific substances (interferon and lysozyme, activation of the immune system, phagocytosis, protective functions of skin. The protective and mobilizing role of the second link is studied: which is triggered in case of occurrence of disease or preexisting diseases: PL mobilized processes of restitution, reparations, compensation, immunity and microcirculation. The authors studied the possibility of aircraft's using to enhance performance, reduce side effects of physical factors, which are often used in the treatment (electric methods, treatment by sound, fresh and mineral water, etc..

  6. Heterodyne displacement interferometer, insensitive for input polarization

    NARCIS (Netherlands)

    Meskers, A.J.H.; Spronck, J.W.; Munnig Schmidt, R.H.

    2014-01-01

    Periodic nonlinearity (PNL) in displacement interferometers is a systematic error source that limits measurement accuracy. The PNL of coaxial heterodyne interferometers is highly influenced by the polarization state and orientation of the source frequencies. In this Letter, we investigate this error

  7. Characteristics of volume polarization holography with linear polarization light

    Science.gov (United States)

    Zang, Jinliang; Wu, An'an; Liu, Ying; Wang, Jue; Lin, Xiao; Tan, Xiaodi; Shimura, Tsutomu; Kuroda, Kazuo

    2015-10-01

    Volume polarization holographic recording in phenanthrenequinone-doped poly(methyl methacrylate) (PQ-PMMA) photopolymer with linear polarized light is obtained. The characteristics of the volume polarization hologram are experimentally investigated. It is found that beyond the paraxial approximation the polarization states of the holographic reconstruction light are generally different from the signal light. Based on vector wave theoretical analyses and material properties, the special exposure condition for correctly holographic reconstruction is obtained and experimentally demonstrated.

  8. Polarized light in optics and spectroscopy

    CERN Document Server

    Kliger, David S

    1990-01-01

    This comprehensive introduction to polarized light provides students and researchers with the background and the specialized knowledge needed to fully utilize polarized light. It provides a basic introduction to the interaction of light with matter for those unfamiliar with photochemistry and photophysics. An in-depth discussion of polarizing optics is also given. Different analytical techniques are introduced and compared and introductions to the use of polarized light in various forms of spectroscopy are provided.Key Features* Starts at a basic level and develops tools for resear

  9. Effects of the input polarization on JET polarimeter horizontal channels

    International Nuclear Information System (INIS)

    Gaudio, P.; Gelfusa, M.; Murari, A.; Orsitto, F.; Boboc, A.

    2013-01-01

    In the past, the analysis of JET polarimetry measurements were carried out only for the vertical channels using a polarimetry propagation code based on the Stokes vector formalism [1,2]. A new propagation code has been developed therefore for the horizontal chords to simulate and interpret the measurements of the Faraday rotation and Cotton–Mouton phase shift in JET. The code has been used to develop a theoretical study to the effect of the input polarization on the eventual quality of the measurements. The results allow choosing the best polarization to optimize the polarimetric measurements for the various experiments

  10. Optical detection dental disease using polarized light

    Science.gov (United States)

    Everett, Matthew J.; Colston, Jr., Billy W.; Sathyam, Ujwal S.; Da Silva, Luiz B.; Fried, Daniel

    2003-01-01

    A polarization sensitive optical imaging system is used to detect changes in polarization in dental tissues to aid the diagnosis of dental disease such as caries. The degree of depolarization is measured by illuminating the dental tissue with polarized light and measuring the polarization state of the backscattered light. The polarization state of this reflected light is analyzed using optical polarimetric imaging techniques. A hand-held fiber optic dental probe is used in vivo to direct the incident beam to the dental tissue and collect the reflected light. To provide depth-resolved characterization of the dental tissue, the polarization diagnostics may be incorporated into optical coherence domain reflectometry and optical coherence tomography (OCDR/OCT) systems, which enables identification of subsurface depolarization sites associated with demineralization of enamel or bone.

  11. Characterization of Partially Polarized Light Fields

    CERN Document Server

    Martínez-Herrero, Rosario; Piquero, Gemma

    2009-01-01

    Polarization involves the vectorial nature of light fields. In current applications of optical science, the electromagnetic description of light with its vector features has been shown to be essential: In practice, optical radiation also exhibits randomness and spatial non-uniformity of the polarization state. Moreover, propagation through photonic devices can alter the correlation properties of the light field, resulting in changes in polarization. All these vectorial properties have been gaining importance in recent years, and they are attracting increasing attention in the literature. This is the framework and the scope of the present book, which includes the authors’ own contributions to these issues.

  12. Hybrid fluorescent layer emitting polarized light

    Directory of Open Access Journals (Sweden)

    Mohammad Mohammadimasoudi

    2017-07-01

    Full Text Available Semiconductor nanorods have anisotropic absorption and emission properties. In this work a hybrid luminescent layer is produced based on a mixture of CdSe/CdS nanorods dispersed in a liquid crystal that is aligned by an electric field and polymerized by UV illumination. The film emits light with polarization ratio 0.6 (polarization contrast 4:1. Clusters of nanorods in liquid crystal can be avoided by applying an AC electric field with sufficient amplitude. This method can be made compatible with large-scale processing on flexible transparent substrates. Thin polarized light emitters can be used in LCD backlights or solar concentrators to increase the efficiency.

  13. A note on polarized light from magnetars

    Energy Technology Data Exchange (ETDEWEB)

    Capparelli, L.M.; Damiano, A.; Polosa, A.D. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN, Rome (Italy); Maiani, L. [CERN, Theory Department, Geneva (Switzerland)

    2017-11-15

    In a recent paper it is claimed that vacuum birefringence has been experimentally observed for the first time by measuring the degree of polarization of visible light from a magnetar candidate, a neutron star with a magnetic field presumably as large as B ∝ 10{sup 13} G. The role of such a strong magnetic field is twofold. First, the surface of the star emits, at each point, polarized light with linear polarization correlated with the orientation of the magnetic field. Depending on the relative orientation of the magnetic axis of the star with the direction to the distant observer, a certain degree of polarization should be visible. Second, the strong magnetic field in the vacuum surrounding the star could enhance the effective degree of polarization observed: vacuum birefringence. We compare experimental data and theoretical expectations concluding that the conditions to support a claim of strong evidence of vacuum birefringence effects are not met. (orig.)

  14. Some Activities with Polarized Light from a Laptop LCD Screen

    Science.gov (United States)

    Fakhruddin, Hasan

    2008-01-01

    The LCD screen of a laptop computer provides a broad, bright, and extended source of polarized light. A number of demonstrations on the properties of polarized light from a laptop computer screens are presented here.

  15. Superconducting Undulator with Variably Polarized Light

    CERN Document Server

    Hwang, Ching Shiang; Ching Fan, Tai; Li, W P; Lin, P H

    2004-01-01

    This study investigates planar in-vacuo superconducting undulators with periodic length of 5 cm (IVSU5) producing linearly and circularly polarized infrared rays or xrays source. The vertically wound racetrack coil is selected for the coil and pole fabrication of the IVSU5. When the up and down magnetic pole arrays with alternative directions rotated wires in the horizontal plane, a helical field radiates circularly polarized light in the electron storage ring, the free electron laser (FEL), and the energy recovery linac (ERL) facilities. Meanwhile, an un-rotated wire is constructed together with the rotated wire on the same undulator is used to switch the linear horizontal and vertical, the right- and left-circular polarization radiation. Given a periodic length of 5 cm and a gap of 23 mm, the maximum magnetic flux density in the helical undulator are Bz = 1.5 T and Bx = 0.5 T when the wires rotated by 20°. This article describes the main factors of the planar and helical undulator design for FEL and...

  16. Single input state, single–mode fiber–based polarization sensitive optical frequency domain imaging by eigenpolarization referencing

    Science.gov (United States)

    Lippok, Norman; Villiger, Martin; Jun, Chang–Su; Bouma, Brett E.

    2015-01-01

    Fiber–based polarization sensitive OFDI is more challenging than free–space implementations. Using multiple input states, fiber–based systems provide sample birefringence information with the benefit of a flexible sample arm but come at the cost of increased system and acquisition complexity, and either reduce acquisition speed or require increased acquisition bandwidth. Here we show that with the calibration of a single polarization state, fiber–based configurations can approach the conceptual simplicity of traditional free–space configurations. We remotely control the polarization state of the light incident at the sample using the eigenpolarization states of a wave plate as a reference, and determine the Jones matrix of the output fiber. We demonstrate this method for polarization sensitive imaging of biological samples. PMID:25927775

  17. Discrete Input Signaling for MISO Visible Light Communication Channels

    KAUST Repository

    Arfaoui, Mohamed Amine

    2017-05-12

    In this paper, we study the achievable secrecy rate of visible light communication (VLC) links for discrete input distributions. We consider single user single eavesdropper multiple-input single-output (MISO) links. In addition, both beamforming and robust beamforming are considered. In the former case, the location of the eavesdropper is assumed to be known, whereas in the latter case, the location of the eavesdropper is unknown. We compare the obtained results with those achieved by some continuous distributions including the truncated generalized normal (TGN) distribution and the uniform distribution. We numerically show that the secrecy rate achieved by the discrete input distribution with a finite support is significantly improved as compared to those achieved by the TGN and the uniform distributions.

  18. Multi detector input and function generator for polarized neutron experiments

    International Nuclear Information System (INIS)

    De Blois, J.; Beunes, A.J.H.; Ende, P. v.d.; Osterholt, E.A.; Rekveldt, M.T.; Schipper, M.N.; Velthuis, S.G.E. te

    1998-01-01

    In this paper a VME module is described for static or stroboscopic measurements with a neutron scattering instrument, consisting essentially of a series of up to 64 3 He neutron detectors around a sample environment. Each detector is provided with an amplifier and a discriminator to separate the neutrons from noise. To reduce the wiring, the discriminator outputs are connected to the module by coding boxes. Two 16-inputs to one-output coding boxes generate serial output codes on a fiber optic connection. This basically fast connection reduces the dead time introduced by the coding, and the influence of environmental noise. With stroboscopic measurements a periodic function is used to affect the sample surrounded by a field coil. Each detected neutron is labeled with a data label containing the detector number and the time of detection with respect to a time reference. The data time base can be programmed on a linear or a nonlinear scale. An external source or an attribute of the periodic function may generate the time reference pulse. A 12-bit DAC connected to the output of an 8 K, 16-bits memory, where the pattern of the current has been stored before, generates the function. The function memory is scanned by the programmable function time base. Attributes are set by the four remaining bits of the memory. One separate detector input connects a monitor detector in the neutron beam with a 32-bit counter/timer that provides measuring on a preset count, preset time or preset frame. (orig.)

  19. Polarization fluctuations in stationary light beams

    International Nuclear Information System (INIS)

    Shevchenko, A.; Setaelae, T.; Kaivola, M.; Friberg, A.T.; Royal Institute of Technology , Department of Microelectronics and Applied Physics; Sweden)

    2009-01-01

    For stationary beams the degree of polarization contains only limited information on time dependent polarization. Two approaches towards assessing a beams polarization dynamics, one based on Poincare and the other on Jones vector formalism, are described leading to the notion of polarization time. Specific examples of partially temporally coherent electromagnetic beams are discussed. (Author)

  20. Efficient propagation of TM polarized light in photonic crystal components exhibiting band gaps for TE polarized light

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Frandsen, Lars Hagedorn; Thorhauge, Morten

    2003-01-01

    D finite-difference-time-domain method. The simulated spectra are in excellent agreement with the experimental results, which show a propagation loss as low as 2.5±4 dB/mm around 1525 nm and bend losses at 2.9±0.2 dB for TM polarized light. We demonstrate a high coupling for TM polarized light......We have investigated the properties of TM polarized light in planar photonic crystal waveguide structures, which exhibit photonic band gaps for TE polarized light. Straight and bent photonic crystal waveguides and couplers have been fabricated in silicon-on-insulator material and modelled using a 3...

  1. Light-matter interactions in a polarization standing wave

    OpenAIRE

    Fang, X.; MacDonald, K.F.; Zheludev, N.I.

    2015-01-01

    We report on the application of polarization standing waves (PSW) to the coherent control of light-matter interactions in planar photonic nanostructures. Such waves, formed by counter-propagating (linear or circular) orthogonally polarized beams can uniquely detect polarization conversion, planar chirality and related asymmetric transmission effects.

  2. Polymer photovoltaic cells sensitive to the circular polarization of light

    Energy Technology Data Exchange (ETDEWEB)

    Gilot, Jan; Abbel, Robert; Lakhwani, Girish; Meijer, E.W.; Schenning, Albertus P.H.J.; Meskers, Stefan C.J. [Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology (Netherlands)

    2010-05-25

    Chiral conjugated polymer is used to construct a photovoltaic cell whose response depends on the circular polarization of the incoming light. The selectivity for left and right polarized light as a function of the thickness of the polymer layer is accounted for by modeling of the optical properties of all layers inside the device. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  3. Simulation of erasure of photoinduced anisotropy by circularly polarized light

    DEFF Research Database (Denmark)

    Sajti, Sz.; Kerekes, Á.; Barabás, M.

    2001-01-01

    The temporal evolution of photoinduced birefringence is investigated on the basis of a model proposed by Pedersen and co-workers, This model is extended for the case of elliptically polarized light, and used to describe the erasure of photoinduced birefringence by circularly polarized light...

  4. [Application of polarized light in purulent-septic surgery].

    Science.gov (United States)

    Desiateryk, V I; Mikhno, S P; Kryvyts'kyĭ, Iu M; Kostiuk, S O

    2002-09-01

    Influence of polarized light on general state and healing of wounds and trophic ulcers in 57 patients with obliterating atherosclerosis of lower extremities, chronic venous insufficiency of extremities, purulent postoperative complications, purulent-septic complications in patients with diabetes mellitus was analyzed. Main mechanisms of the polarized light action in "Bioptron" apparatus were enlighted, effective schemes of its usage were determined.

  5. Propagation of polarized light in turbid media: simulated animation sequences

    OpenAIRE

    Yao, Gang; Wang, Lihong V.

    2000-01-01

    A time-resolved Monte Carlo technique was used to simulate the propagation of polarized light in turbid media. Calculated quantities include the reflection Mueller matrices, the transmission Mueller matrices, and the degree of polarization (DOP). The effects of the polarization state of the incident light and of the size of scatterers on the propagation of DOP were studied. Results are shown in animation sequences.

  6. Lunar skylight polarization signal polluted by urban lighting

    Science.gov (United States)

    Kyba, C. C. M.; Ruhtz, T.; Fischer, J.; Hölker, F.

    2011-12-01

    On clear moonlit nights, a band of highly polarized light stretches across the sky at a 90 degree angle from the moon, and it was recently demonstrated that nocturnal organisms are able to navigate based on it. Urban skyglow is believed to be almost unpolarized, and is therefore expected to dilute this unique partially linearly polarized signal. We found that urban skyglow has a greater than expected degree of linear polarization (p = 8.6 ± 0.3%), and confirmed that its presence diminishes the natural lunar polarization signal. We also observed that the degree of linear polarization can be reduced as the moon rises, due to the misalignment between the polarization angles of the skyglow and scattered moonlight. Under near ideal observing conditions, we found that the lunar polarization signal was clearly visible (p = 29.2 ± 0.8%) at a site with minimal light pollution 28 km from Berlin's center, but was reduced (p = 11.3 ± 0.3%) within the city itself. Daytime measurements indicate that without skyglow p would likely be in excess of 50%. These results indicate that nocturnal animal navigation systems based on perceiving polarized scattered moonlight likely fail to operate properly in highly light-polluted areas, and that future light pollution models must take polarization into account.

  7. Self-Induced Light Polarization Rotation in Azobenzene-Containing Polymers

    DEFF Research Database (Denmark)

    Nikolova, L.; Nedelchev, L.; Todorov, T.

    2000-01-01

    We report here a light-induced phenomenon--a self-induced rotation of the azimuth of elliptically polarized light passing through photobirefringent azopolymers. The experiments are carried out with films of amorphous and liquid-crystalline polymers. It has been shown that the induced rotation angle...... depends on the ellipticity of the input light. A theoretical analysis of the phenomenon has been done and it has been shown that light induces chiral structure in the polymer films. (C) 2000 American Institute of Physics. [S0003-6951(00)02731-5]....

  8. Polarized light modulates light-dependent magnetic compass orientation in birds

    Science.gov (United States)

    Muheim, Rachel; Sjöberg, Sissel; Pinzon-Rodriguez, Atticus

    2016-01-01

    Magnetoreception of the light-dependent magnetic compass in birds is suggested to be mediated by a radical-pair mechanism taking place in the avian retina. Biophysical models on magnetic field effects on radical pairs generally assume that the light activating the magnetoreceptor molecules is nondirectional and unpolarized, and that light absorption is isotropic. However, natural skylight enters the avian retina unidirectionally, through the cornea and the lens, and is often partially polarized. In addition, cryptochromes, the putative magnetoreceptor molecules, absorb light anisotropically, i.e., they preferentially absorb light of a specific direction and polarization, implying that the light-dependent magnetic compass is intrinsically polarization sensitive. To test putative interactions between the avian magnetic compass and polarized light, we developed a spatial orientation assay and trained zebra finches to magnetic and/or overhead polarized light cues in a four-arm “plus” maze. The birds did not use overhead polarized light near the zenith for sky compass orientation. Instead, overhead polarized light modulated light-dependent magnetic compass orientation, i.e., how the birds perceive the magnetic field. Birds were well oriented when tested with the polarized light axis aligned parallel to the magnetic field. When the polarized light axis was aligned perpendicular to the magnetic field, the birds became disoriented. These findings are the first behavioral evidence to our knowledge for a direct interaction between polarized light and the light-dependent magnetic compass in an animal. They reveal a fundamentally new property of the radical pair-based magnetoreceptor with key implications for how birds and other animals perceive the Earth’s magnetic field. PMID:26811473

  9. Do cephalopods communicate using polarized light reflections from their skin?

    Science.gov (United States)

    Mäthger, Lydia M; Shashar, Nadav; Hanlon, Roger T

    2009-07-01

    Cephalopods (squid, cuttlefish and octopus) are probably best known for their ability to change color and pattern for camouflage and communication. This is made possible by their complex skin, which contains pigmented chromatophore organs and structural light reflectors (iridophores and leucophores). Iridophores create colorful and linearly polarized reflective patterns. Equally interesting, the photoreceptors of cephalopod eyes are arranged in a way to give these animals the ability to detect the linear polarization of incoming light. The capacity to detect polarized light may have a variety of functions, such as prey detection, navigation, orientation and contrast enhancement. Because the skin of cephalopods can produce polarized reflective patterns, it has been postulated that cephalopods could communicate intraspecifically through this visual system. The term 'hidden' or 'private' communication channel has been given to this concept because many cephalopod predators may not be able to see their polarized reflective patterns. We review the evidence for polarization vision as well as polarization signaling in some cephalopod species and provide examples that tend to support the notion--currently unproven--that some cephalopods communicate using polarized light signals.

  10. Physical processes in azobenzene polymers on irradiation with polarized light

    DEFF Research Database (Denmark)

    Holme, N.C.R.; Nikolova, L.; Norris, T.B.

    1999-01-01

    . A transition route based on experimental results for the theoretically calculated energy level scheme is proposed. Physical observations of surface relief in thin films of azobenzene polymers when irradiated with polarized light are reported. These include two beam polarization holographic observations...

  11. Using Polarization features of visible light for automatic landmine detection

    NARCIS (Netherlands)

    Jong, W. de; Schavemaker, J.G.M.

    2007-01-01

    This chapter describes the usage of polarization features of visible light for automatic landmine detection. The first section gives an introduction to land-mine detection and the usage of camera systems. In section 2 detection concepts and methods that use polarization features are described.

  12. The effects of polarized light therapy in pressure ulcer healing

    Directory of Open Access Journals (Sweden)

    Đurović Aleksandar

    2008-01-01

    Full Text Available Background/Aim. Neglecting polarized light as an adjuvant therapy for pressure ulcers and methodology distinctions in the trials engaging polarized light are the reasons for many dilemmas and contradictions. The aim of this study was to establish the effects of polarized light therapy in pressure ulcer healing. Methods. This prospective randomized single-blind study involved 40 patients with stage I-III of pressure ulcer. The patients in the experimental group (E were subjected, besides polarized light therapy, to standard wound cleaning and dressing. Standard wound cleaning and dressing were the only treatment used in the control group (C. A polarized light source was a Bioptron lamp. Polarized light therapy was applied for six min daily, five times a week, four weeks. The Pressure Ulcer Scale for Healing (PUSH was used in the assessment of outcome. Statistic analysis included Mann Whitney Test, Fisher Exact Test, Wilcoxon Signed Rank test. Results. There were significant differences between the groups at the end of the treatment regarding the surface of pressure ulcer (E: 10.80±19.18; C: 22,97±25,47; p = 0.0005, rank of pressure ulcer (E: 5.90±2.48; C: 8.6±1.05; p = 0.0005 and total PUSH score (E: 7.35±3.17; C: 11.85±2.35; p = 0,0003. The patients in the experimental group had significantly better values of the parameters monitored than the patients in the control group. Conclusion. After a four-week polarized light therapy 20 patients with stage I-III ulcer had significant improvement in pressure ulcer healing, so it could be useful to apply polarized light in the treatment of pressure ulcers.

  13. The effects of polarized light therapy in pressure ulcer healing.

    Science.gov (United States)

    Durović, Aleksandar; Marić, Dragan; Brdareski, Zorica; Jevtić, Miodrag; Durdević, Slavisa

    2008-12-01

    Neglecting polarized light as an adjuvant therapy for pressure ulcers and methodology distinctions in the trials engaging polarized light are the reasons for many dilemmas and contradictions. The aim of this study was to establish the effects of polarized light therapy in pressure ulcer healing. This prospective randomized single-blind study involved 40 patients with stage I-III of pressure ulcer. The patients in the experimental group (E) were subjected, besides polarized light therapy, to standard wound cleaning and dressing. Standard wound cleaning and dressing were the only treatment used in the control group (C). A polarized light source was a Bioptron lamp. Polarized light therapy was applied for six min daily, five times a week, four weeks. The Pressure Ulcer Scale for Healing (PUSH) was used in the assessment of outcome. Statistic analysis included Mann Whitney Test, Fisher Exact Test, Wilcoxon Signed Rank test. There were significant differences between the groups at the end of the treatment regarding the surface of pressure ulcer (E: 10.80 +/- 19.18; C: 22,97 +/- 25,47; p = 0.0005), rank of pressure ulcer (E: 5.90 +/- 2.48; C: 8.6 +/- 1.05; p = 0.0005) and total PUSH score (E: 7.35 +/- 3.17; C: 11.85 +/- 2.35; p = 0,0003). The patients in the experimental group had significantly better values of the parameters monitored than the patients in the control group. After a four-week polarized light therapy 20 patients with stage I-III ulcer had significant improvement in pressure ulcer healing, so it could be useful to apply polarized light in the treatment of pressure ulcers.

  14. Robust reflective ghost imaging against different partially polarized thermal light

    Science.gov (United States)

    Li, Hong-Guo; Wang, Yan; Zhang, Rui-Xue; Zhang, De-Jian; Liu, Hong-Chao; Li, Zong-Guo; Xiong, Jun

    2018-03-01

    We theoretically study the influence of degree of polarization (DOP) of thermal light on the contrast-to-noise ratio (CNR) of the reflective ghost imaging (RGI), which is a novel and indirect imaging modality. An expression for the CNR of RGI with partially polarized thermal light is carefully derived, which suggests a weak dependence of CNR on the DOP, especially when the ratio of the object size to the speckle size of thermal light has a large value. Different from conventional imaging approaches, our work reveals that RGI is much more robust against the DOP of the light source, which thereby has advantages in practical applications, such as remote sensing.

  15. Influence of geomagnetic energy inputs in the polar cap on the upper atmosphere during geomagnetic storms

    Science.gov (United States)

    Deng, Y.; Sheng, C.; Huang, Y.; Maute, A. I.; Lu, Y.

    2016-12-01

    Large Poynting flux has been observed in the polar cap by Defense Meteorological Satellite Program (DMSP) satellites during the main phase of the August 5, 2011 storm, the magnitude of which is comparable to that in the auroral zone. In order to understand the mechanisms for the observed large Poynting flux in the polar cap, the particle precipitation and small-scale electric field variability along DMSP satellite trajectory has been studied. Meanwhile, the global ionosphere-thermosphere model (GITM) has been run to examine the relative contribution of convection pattern and conductance to the polar cap Poynting flux enhancement. The influence of energy inputs in the polar cap including Joule heating related to both large-scale and small-scale electric field and soft particle precipitation on the thermosphere has been examined through the analysis of the GRACE neutral density observations and GITM simulations with different forcings. This study will help to illustrate the mechanisms and impacts of the polar cap energy inputs.

  16. A switchable light-input, light-output system modelled and constructed in yeast

    Directory of Open Access Journals (Sweden)

    Kozma-Bognar Laszlo

    2009-09-01

    Full Text Available Abstract Background Advances in synthetic biology will require spatio-temporal regulation of biological processes in heterologous host cells. We develop a light-switchable, two-hybrid interaction in yeast, based upon the Arabidopsis proteins PHYTOCHROME A and FAR-RED ELONGATED HYPOCOTYL 1-LIKE. Light input to this regulatory module allows dynamic control of a light-emitting LUCIFERASE reporter gene, which we detect by real-time imaging of yeast colonies on solid media. Results The reversible activation of the phytochrome by red light, and its inactivation by far-red light, is retained. We use this quantitative readout to construct a mathematical model that matches the system's behaviour and predicts the molecular targets for future manipulation. Conclusion Our model, methods and materials together constitute a novel system for a eukaryotic host with the potential to convert a dynamic pattern of light input into a predictable gene expression response. This system could be applied for the regulation of genetic networks - both known and synthetic.

  17. PHYSIOLOGICAL MECHANISMS OF POLARIZED LIGHT INFLUENCE ON PAIN

    Directory of Open Access Journals (Sweden)

    S. О. Gulyar

    2016-06-01

    Full Text Available There are presented experimental evidences of BIOPTRON device polarized light influence on the acupuncture points and pain locus. It is proved that PILER-light can induce analgesia which depends on the choice of the application zone, exposure and nature of pain (tonic, acute or visceral. Analgesic response has systemic character and is accompanied by participation of opioidergic nociceptive system

  18. PHYSIOLOGICAL MECHANISMS OF POLARIZED LIGHT INFLUENCE ON PAIN

    OpenAIRE

    S. О. Gulyar; Z. А. Tamarova

    2016-01-01

    There are presented experimental evidences of BIOPTRON device polarized light influence on the acupuncture points and pain locus. It is proved that PILER-light can induce analgesia which depends on the choice of the application zone, exposure and nature of pain (tonic, acute or visceral). Analgesic response has systemic character and is accompanied by participation of opioidergic nociceptive system

  19. Angle-dependent rotation of calcite in elliptically polarized light

    Science.gov (United States)

    Herne, Catherine M.; Cartwright, Natalie A.; Cattani, Matthew T.; Tracy, Lucas A.

    2017-08-01

    Calcite crystals trapped in an elliptically polarized laser field exhibit intriguing rotational motion. In this paper, we show measurements of the angle-dependent motion, and discuss how the motion of birefringent calcite can be used to develop a reliable and efficient process for determining the polarization ellipticity and orientation of a laser mode. The crystals experience torque in two ways: from the transfer of spin angular momentum (SAM) from the circular polarization component of the light, and from a torque due to the linear polarization component of the light that acts to align the optic axis of the crystal with the polarization axis of the light. These torques alternatingly compete with and amplify each other, creating an oscillating rotational crystal velocity. We model the behavior as a rigid body in an angle-dependent torque. We experimentally demonstrate the dependence of the rotational velocity on the angular orientation of the crystal by placing the crystals in a sample solution in our trapping region, and observing their behavior under different polarization modes. Measurements are made by acquiring information simultaneously from a quadrant photodiode collecting the driving light after it passes through the sample region, and by imaging the crystal motion onto a camera. We finish by illustrating how to use this model to predict the ellipticity of a laser mode from rotational motion of birefringent crystals.

  20. Multiple scattering of polarized light in a turbid medium

    International Nuclear Information System (INIS)

    Gorodnichev, E. E.; Kuzovlev, A. I.; Rogozkin, D. B.

    2007-01-01

    It is shown that multiple scattering of polarized light in a turbid medium can be represented as independent propagation of three basic modes: intensity and linearly and circularly polarized modes. Weak interaction between the basic modes can be described by perturbation theory and gives rise to 'overtones' (additional polarization modes). Transport equations for the basic and additional modes are derived from a vector radiative transfer equation. Analytical solutions to these equations are found in the practically important cases of diffusive light propagation and small-angle multiple scattering. The results obtained are in good agreement with experimental and numerical results and provide an explanation for the experimentally observed difference in depolarization between linearly and circularly polarized waves

  1. Broadband asymmetric waveguiding of light without polarization limitations.

    Science.gov (United States)

    Xu, Yadong; Gu, Chendong; Hou, Bo; Lai, Yun; Li, Jensen; Chen, Huanyang

    2013-01-01

    Optical diodes are fundamental elements for optical computing and information processing. Attempts to realize such non-reciprocal propagation of light by breaking the time-reversal symmetry include using indirect interband photonic transitions, the magneto-optical effect, optical nonlinearity or photonic crystals. Alternatively, asymmetric reciprocal transmission of light has been proposed in photonic metamaterial structures for either circularly or linearly polarized waves. Here we employ the recent concept of gradient index metamaterials to demonstrate a waveguide with asymmetric propagation of light, independent of polarization. The device blocks both transverse electric and magnetic polarized modes in one direction but transmits them in the other for a broadband spectrum. Unlike previous works using chiral properties of metamaterials, our device is based on the principle of momentum symmetry breaking at interfaces with phase discontinuities. Experiments in the microwave region verify our findings, which may pave the way to feasible passive optical diodes.

  2. On the polarization of light in atmospheres and oceans

    Science.gov (United States)

    Yang, P.; Kattawar, G. W.; Mishchenko, M. I.

    2016-12-01

    In this talk, we will briefly review the genesis and evolution of the polarization of light, dating back to the Vikings' questionable use of sunstones for navigation. Also to be presented are the first use of polarimetry in the study of planetary atmospheres and stars as well as the latest results on the use of polarization by both terrestrial and marine organisms. In particular, our presentation will focus on the representation of the polarization characteristics of light in terms of the Stokes vector-Mueller matrix formalism. In addition, we will discuss the features of the polarization properties of nonspherical particles. Furthermore, we will illustrate the great potential of using the polarization properties of light in downstream applications, particularly remote sensing of the optical and microphysical properties of airborne dust and ice crystals. We will also show the effect of coherence of the illuminating source on the polarization properties of atmospheric particles since sunlight only has a lateral coherence length of roughly 60 μm.

  3. Optical image encryption method based on incoherent imaging and polarized light encoding

    Science.gov (United States)

    Wang, Q.; Xiong, D.; Alfalou, A.; Brosseau, C.

    2018-05-01

    We propose an incoherent encoding system for image encryption based on a polarized encoding method combined with an incoherent imaging. Incoherent imaging is the core component of this proposal, in which the incoherent point-spread function (PSF) of the imaging system serves as the main key to encode the input intensity distribution thanks to a convolution operation. An array of retarders and polarizers is placed on the input plane of the imaging structure to encrypt the polarized state of light based on Mueller polarization calculus. The proposal makes full use of randomness of polarization parameters and incoherent PSF so that a multidimensional key space is generated to deal with illegal attacks. Mueller polarization calculus and incoherent illumination of imaging structure ensure that only intensity information is manipulated. Another key advantage is that complicated processing and recording related to a complex-valued signal are avoided. The encoded information is just an intensity distribution, which is advantageous for data storage and transition because information expansion accompanying conventional encryption methods is also avoided. The decryption procedure can be performed digitally or using optoelectronic devices. Numerical simulation tests demonstrate the validity of the proposed scheme.

  4. Polarized backlight unit using a polarization-preserving light-redirecting film for improving luminance gain

    Science.gov (United States)

    Moon, Jeongmin; Lee, Sungrae; Oh, Kyunghwan

    2015-05-01

    We proposed and demonstrated a polarized backlight unit (BLU) configuration with a new light-redirecting film (LRF) to improve the luminance gain and light transmittance in liquid crystal displays. We combined a very low birefringence triacetyl cellulose (TAC) base layer with UV-cured prismatic patterns in a mass-producible process to demonstrate a polarization-preserving LRF. Detailed analyses of the states of polarization (SOP) through the LRF were reported. We also fabricated a 7-in. edge-lit BLU using the new LRF. We found that the light directing capability of the new LRF was equivalent to that of a conventional prism film whose base layer was a poly(ethylene terephthalate) (PET) film, and that the new LRF successfully suppressed random polarization changes of the transmitted light. Utilizing these new advantages, we obtained 68% transmittance through the polarizer over the BLU with the new LRF, which was about 1.3-fold that for the BLU with the conventional prism film (54%). We also obtained 127% luminance gain using the new LRF, which was equivalent to that of the conventional prism film. Here, the luminance gain is referred to as the amount of increase in luminance on the surface normal of the light-guiding plate without any film.

  5. Polarized light improves cutaneous healing on diabetic rats

    Science.gov (United States)

    Ramalho, Luciana Maria Pedreira; Oliveira, Priscila Chagas; Marques, Aparecida Maria Cordeiro; Barbosa Pinheiro, Antonio L.

    2010-02-01

    The aim of this study was to evaluate the healing of 3rd degree burn on diabetic rats submitted or not to treatment with Polarized Light. Diabetes mellitus (Streptozotocin, 60mg/kg) was induced on 45 male Wistar albinus rats and a third degree burn (1.5× 1.5cm) was created in the dorsum of each animal under general anesthesia. After a regular quarantine period, the animals were randomly distributed into three groups as follows: G1: control (no treatment, n =15); G2: Polarized Light (λ=400-2000nm, 20J/cm2) and G3: Polarized Light (λ=400-2000nm, 40J/cm2). The phototherapy performed on group G2 was Polarized Light dose 20J/cm2 and G3 was Polarized Light dose 40J/cm2 (Bioptron®, λ400-2000 nm, 40mW; 2.4J/cm2 per minute; Φ +/- 5.5 cm; Bioptron AG, Monchaltorf, Switzerland). The phototherapy started immediately post-burning and was repeated daily until the day before the animal death. The energy was applied transcutaneously respecting the focal distance of 10cm as recommended by the manufacturer. The dose was 20 or 40J/cm2 (4min 15s or 8min.and 30s). At each time point chosen (7, 14, and 21 days post-burning) and following macroscopic examination, each animal was killed by an overdose of general anesthesia. Slides were stained with HE, Sirius Red, and CK AE1/AE3 antibody. Qualitative and semi-quantitative analyses were performed under light microscopy. The animals submitted to phototherapy (20J/cm2) showed significant differences on regards revascularization and epithelialization. The use of 20J/cm2 was effective on improving the healing of third degree buns on diabetic animals at both early and late stages of the repair.

  6. Visual stimulation switches the polarity of excitatory input to starburst amacrine cells.

    Science.gov (United States)

    Vlasits, Anna L; Bos, Rémi; Morrie, Ryan D; Fortuny, Cécile; Flannery, John G; Feller, Marla B; Rivlin-Etzion, Michal

    2014-09-03

    Direction-selective ganglion cells (DSGCs) are tuned to motion in one direction. Starburst amacrine cells (SACs) are thought to mediate this direction selectivity through precise anatomical wiring to DSGCs. Nevertheless, we previously found that visual adaptation can reverse DSGCs's directional tuning, overcoming the circuit anatomy. Here we explore the role of SACs in the generation and adaptation of direction selectivity. First, using pharmacogenetics and two-photon calcium imaging, we validate that SACs are necessary for direction selectivity. Next, we demonstrate that exposure to an adaptive stimulus dramatically alters SACs' synaptic inputs. Specifically, after visual adaptation, On-SACs lose their excitatory input during light onset but gain an excitatory input during light offset. Our data suggest that visual stimulation alters the interactions between rod- and cone-mediated inputs that converge on the terminals of On-cone BCs. These results demonstrate how the sensory environment can modify computations performed by anatomically defined neuronal circuits. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Can invertebrates see the e-vector of polarization as a separate modality of light?

    OpenAIRE

    Labhart, Thomas

    2016-01-01

    ABSTRACT The visual world is rich in linearly polarized light stimuli, which are hidden from the human eye. But many invertebrate species make use of polarized light as a source of valuable visual information. However, exploiting light polarization does not necessarily imply that the electric (e)-vector orientation of polarized light can be perceived as a separate modality of light. In this Review, I address the question of whether invertebrates can detect specific e-vector orientations in a ...

  8. Control of polarization rotation in nonlinear propagation of fully structured light

    Science.gov (United States)

    Gibson, Christopher J.; Bevington, Patrick; Oppo, Gian-Luca; Yao, Alison M.

    2018-03-01

    Knowing and controlling the spatial polarization distribution of a beam is of importance in applications such as optical tweezing, imaging, material processing, and communications. Here we show how the polarization distribution is affected by both linear and nonlinear (self-focusing) propagation. We derive an analytical expression for the polarization rotation of fully structured light (FSL) beams during linear propagation and show that the observed rotation is due entirely to the difference in Gouy phase between the two eigenmodes comprising the FSL beams, in excellent agreement with numerical simulations. We also explore the effect of cross-phase modulation due to a self-focusing (Kerr) nonlinearity and show that polarization rotation can be controlled by changing the eigenmodes of the superposition, and physical parameters such as the beam size, the amount of Kerr nonlinearity, and the input power. Finally, we show that by biasing cylindrical vector beams to have elliptical polarization, we can vary the polarization state from radial through spiral to azimuthal using nonlinear propagation.

  9. Ventral polarization vision in tabanids: horseflies and deerflies (Diptera: Tabanidae) are attracted to horizontally polarized light

    Science.gov (United States)

    Horváth, Gábor; Majer, József; Horváth, Loránd; Szivák, Ildikó; Kriska, György

    2008-11-01

    Adult tabanid flies (horseflies and deerflies) are terrestrial and lay their eggs onto marsh plants near bodies of fresh water because the larvae develop in water or mud. To know how tabanids locate their host animals, terrestrial rendezvous sites and egg-laying places would be very useful for control measures against them, because the hematophagous females are primary/secondary vectors of some severe animal/human diseases/parasites. Thus, in choice experiments performed in the field we studied the behavior of tabanids governed by linearly polarized light. We present here evidence for positive polarotaxis, i.e., attraction to horizontally polarized light stimulating the ventral eye region, in both males and females of 27 tabanid species. The novelty of our findings is that positive polarotaxis has been described earlier only in connection with the water detection of some aquatic insects ovipositing directly into water. A further particularity of our discovery is that in the order Diptera and among blood-sucking insects the studied tabanids are the first known species possessing ventral polarization vision and definite polarization-sensitive behavior with known functions. The polarotaxis in tabanid flies makes it possible to develop new optically luring traps being more efficient than the existing ones based on the attraction of tabanids by the intensity and/or color of reflected light.

  10. Reversible Shaping of Microwells by Polarized Light Irradiation

    Directory of Open Access Journals (Sweden)

    Federica Pirani

    2017-01-01

    Full Text Available In the last years, stimuli-responsive polymeric materials have attracted great interest, due to their low cost and ease of structuration over large areas combined with the possibility to actively manipulate their properties. In this work, we propose a polymeric pattern of soft-imprinted microwells containing azobenzene molecules. The shape of individual elements of the pattern can be controlled after fabrication by irradiation with properly polarized light. By taking advantage of the light responsivity of the azobenzene compound, we demonstrate the possibility to reversibly modulate a contraction-expansion of wells from an initial round shape to very narrow slits. We also show that the initial shape of the microconcavities can be restored by flipping the polarization by 90°. The possibility to reversibly control the final shape of individual elements of structured surfaces offers the opportunity to engineer surface properties dynamically, thus opening new perspectives for several applications.

  11. Discovery of polarized light scattered by dust around Alpha Orionis

    Science.gov (United States)

    Mcmillan, R. S.; Tapia, S.

    1978-01-01

    Following the suggestion by Jura and Jacoby (1976), linearly polarized blue continuum starlight scattered by the dust shell around the M2 Iab star Alpha Orionis (Betelgeuse) has been discovered. The polarization has been traced in the NE, NW, SE, and SW directions and has positive (tangential) orientation. Some asymmetry of the optical depth in the shell exists 15 and 30 arcsec from the star. In the NE direction the polarization was measured as far as 90 arcsec (17,000 AU) from the star. The dependence of the average intensity of the scattered light from the nebula on angular distance from the star is more consistent with an inverse-square density law than with inverse 1.5 or inverse-cube laws. Assuming that the density is proportional to the inverse square of distance from the star, the scattering optical depth in blue light along a radius of 0.03 arcsec is no more than 0.15 + or - 0.05. Future observations of the wavelength dependence of polarization will allow a determination of grain size.

  12. Optical-Fiber Fluorosensors With Polarized Light Sources

    Science.gov (United States)

    Egalon, Claudio O.; Rogowski, Robert S.

    1995-01-01

    Chemiluminescent and/or fluorescent molecules in optical-fiber fluorosensors oriented with light-emitting dipoles along transverse axis. Sensor of proposed type captures greater fraction of chemiluminescence or fluorescence and transmits it to photodetector. Transverse polarization increases sensitivity. Basic principles of optical-fiber fluorosensors described in "Making Optical-Fiber Chemical Sensors More Sensitive" (LAR-14525), "Improved Optical-Fiber Chemical Sensors" (LAR-14607), and "Improved Optical-Fiber Temperature Sensors" (LAR-14647).

  13. Super-resolution longitudinally polarized light needle achieved by tightly focusing radially polarized beams

    Science.gov (United States)

    Shi, Chang-kun; Nie, Zhong-quan; Tian, Yan-ting; Liu, Chao; Zhao, Yong-chuang; Jia, Bao-hua

    2018-01-01

    Based on the vector diffraction theory, a super-resolution longitudinally polarized optical needle with ultra-long depth of focus ( DOF) is generated by tightly focusing a radially polarized beam that is modulated by a self-designed ternary hybrid (phase/amplitude) filter (THF). Both the phase and the amplitude patterns of THF are judiciously optimized by the versatile particle swarm optimization (PSO) searching algorithm. For the focusing configuration with a combination of a high numerical aperture ( NA) and the optimized sine-shaped THFs, an optical needle with the full width at half maximum ( FWHM) of 0.414λ and the DOF of 7.58λ is accessed, which corresponds to an aspect ratio of 18.3. The demonstrated longitudinally polarized super-resolution light needle with high aspect ratio opens up broad applications in high-density optical data storage, nano-photolithography, super-resolution imaging and high-efficiency particle trapping.

  14. Switchable polarization rotation of visible light using a plasmonic metasurface

    Directory of Open Access Journals (Sweden)

    Stuart K. Earl

    2017-01-01

    Full Text Available A metasurface comprising an array of silver nanorods supported by a thin film of the phase change material vanadium dioxide is used to rotate the primary polarization axis of visible light at a pre-determined wavelength. The dimensions of the rods were selected such that, across the two phases of vanadium dioxide, the two lateral localized plasmon resonances (in the plane of the metasurface occur at the same wavelength. Illumination with linearly polarized light at 45° to the principal axes of the rod metasurface enables excitation of both of these resonances. Modulating the phase of the underlying substrate, we show that it is possible to reversibly switch which axis of the metasurface is resonant at the operating wavelength. Analysis of the resulting Stokes parameters indicates that the orientation of the principal linear polarization axis of the reflected signal is rotated by 90° around these wavelengths. Dynamic metasurfaces such as these have the potential to form the basis of an ultra-compact, low-energy multiplexer or router for an optical signal.

  15. Multiangular hyperspectral investigation of polarized light in case 2 waters

    Science.gov (United States)

    Tonizzo, A.; Zhou, J.; Gilerson, A.; Chowdhary, J.; Gross, B.; Moshary, F.; Ahmed, S.

    2009-09-01

    The focus of this work is on the dependence of in situ hyperspectral and multiangular polarized data on the size distribution and refractive index of the suspended particles. Underwater polarization measurements were obtained using a polarimeter developed at the Optical Remote Sensing Laboratory of the City College of New York, NY. The degree of polarization (DOP) of the underwater light field in coastal environments was measured and the water-leaving polarized radiance was derived. In-water optical properties were also measured with an ac-9 (WET Labs). Absorption and attenuation spectra are then used to derive information on the dissolved and suspend components in the water medium which are used in a vector radiative transfer code which provides the upwelling radiance. The model was run for various values of the refractive index of mineral particles until the modeled DOP matched the measured one. The relationship between the intensity of the maximum of the DOP and both the refractive index of the mineral particles and the shapes of their size distributions is analyzed in detail.

  16. Photonic Heterostructures with Properties of Ferroelectrics and Light Polarizers

    Energy Technology Data Exchange (ETDEWEB)

    Palto, S. P., E-mail: palto@online.ru; Draginda, Yu. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2010-11-15

    The optical and electro-optical properties of a new type of photonic heterostructure composed of alternating ferroelectric molecular layers and optically anisotropic layers of another material are considered. A numerical simulation of the real prototype of this heterostructure, which can be prepared by the Langmuir-Blodgett method from layers of a ferroelectric copolymer (polyvinylidene fluoride trifluoroethylene) and an azo dye with photoinduced optical anisotropy, has been performed. It is shown that this heterostructure has pronounced polarization optical properties and yields a significant change in the polarization state of light at the photonic band edges in the ranges of the maximum density of photon states. The latter property can be used to obtain an enhanced electro-optic effect at small spectral shifts of the photonic band (the latter can be provided by the piezoelectric effect in ferroelectric layers).

  17. Spin-polarized light-emitting diodes based on organic bipolar spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Vardeny, Zeev Valentine; Nguyen, Tho Duc; Ehrenfreund, Eitan Avraham

    2017-10-25

    Spin-polarized organic light-emitting diodes are provided. Such spin-polarized organic light-emitting diodes incorporate ferromagnetic electrodes and show considerable spin-valve magneto-electroluminescence and magneto-conductivity responses, with voltage and temperature dependencies that originate from the bipolar spin-polarized space charge limited current.

  18. Measuring polarization dependent dispersion of non-polarizing beam splitter cubes with spectrally resolved white light interferometry

    Science.gov (United States)

    Csonti, K.; Hanyecz, V.; Mészáros, G.; Kovács, A. P.

    2017-06-01

    In this work we have measured the group-delay dispersion of an empty Michelson interferometer for s- and p-polarized light beams applying two different non-polarizing beam splitter cubes. The interference pattern appearing at the output of the interferometer was resolved with two different spectrometers. It was found that the group-delay dispersion of the empty interferometer depended on the polarization directions in case of both beam splitter cubes. The results were checked by inserting a glass plate in the sample arm of the interferometer and similar difference was obtained for the two polarization directions. These results show that to reach high precision, linearly polarized white light beam should be used and the residual dispersion of the empty interferometer should be measured at both polarization directions.

  19. Performance comparison of polarized white light emitting diodes using wire-grid polarizers with polymeric and glass substrates

    Science.gov (United States)

    Su, Jung-Chieh; Chou, Shih-Chieh

    2018-03-01

    Polarized white light emitting diodes (WLEDs) packaged with reflective metal wire-grid polarizer of polymeric and glass substrates were investigated. The performance comparison of polymeric wire-grid polarizer film (WGF) and nano wire-grid polarizer (NWGP) with glass substrate was evaluated. The transverse electric field (TE) polarization transmittance of WGF is less than that of NWGP due to its smaller grid parameters. Despite of the higher duty cycle of WGF, the angular-dependent extinction ratio (ER) of the polarized WLEDs (PWLEDs) with WGF is higher than that of with NWGP. Regarding increasing drive currents, the PWLEDs with NWGP had better color stability than that with WGF due to better substrate thermal stability. In summary, linewidth, period and substrate material are the crucial factors for the PWLED packaging using wire grid polarizer.

  20. Polarization characteristics of radiation in both 'light' and conventional undulators

    Science.gov (United States)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.; Strokov, S. A.

    2017-07-01

    As a rule, an intensity spectrum of undulator radiation (UR) is calculated by using the classical approach, even for electron energy higher than 10 GeV. Such a spectrum is determined by an electron trajectory in an undulator while neglecting radiation loss. Using Planck's law, the UR photon spectrum can be calculated from the obtained intensity spectrum, for both linear and nonlinear regimes. The electron radiation process in a field of strong electromagnetic waves is considered within the quantum electrodynamics framework, using the Compton scattering process or radiation in a 'light' undulator. A comparison was made of the results from using these two approaches, for UR spectra generated by 250-GeV electrons in an undulator with a 11.5-mm period; this comparison shows that they coincide with high accuracy. The characteristics of the collimated UR beam (i.e. spectrum and circular polarization) were simulated while taking into account the discrete process of photon emission along an electron trajectory in both undulator types. Both spectral photon distributions and polarization dependence on photon energy are 'smoothed', in comparison to that expected for a long undulator-the latter of which considers the ILC positron source (ILC Technical Design Report).

  1. Quantitative polarized light microscopy of unstained mammalian cochlear sections

    Science.gov (United States)

    Kalwani, Neil M.; Ong, Cheng Ai; Lysaght, Andrew C.; Haward, Simon J.; McKinley, Gareth H.; Stankovic, Konstantina M.

    2013-02-01

    Hearing loss is the most common sensory deficit in the world, and most frequently it originates in the inner ear. Yet, the inner ear has been difficult to access for diagnosis because of its small size, delicate nature, complex three-dimensional anatomy, and encasement in the densest bone in the body. Evolving optical methods are promising to afford cellular diagnosis of pathologic changes in the inner ear. To appropriately interpret results from these emerging technologies, it is important to characterize optical properties of cochlear tissues. Here, we focus on that characterization using quantitative polarized light microscopy (qPLM) applied to unstained cochlear sections of the mouse, a common animal model of human hearing loss. We find that the most birefringent cochlear materials are collagen fibrils and myelin. Retardance of the otic capsule, the spiral ligament, and the basilar membrane are substantially higher than that of other cochlear structures. Retardance of the spiral ligament and the basilar membrane decrease from the cochlear base to the apex, compared with the more uniform retardance of other structures. The intricate structural details revealed by qPLM of unstained cochlear sections ex vivo strongly motivate future application of polarization-sensitive optical coherence tomography to human cochlea in vivo.

  2. Theory and analysis of a large field polarization imaging system with obliquely incident light.

    Science.gov (United States)

    Lu, Xiaotian; Jin, Weiqi; Li, Li; Wang, Xia; Qiu, Su; Liu, Jing

    2018-02-05

    Polarization imaging technology provides information about not only the irradiance of a target but also the polarization degree and angle of polarization, which indicates extensive application potential. However, polarization imaging theory is based on paraxial optics. When a beam of obliquely incident light passes an analyser, the direction of light propagation is not perpendicular to the surface of the analyser and the applicability of the traditional paraxial optical polarization imaging theory is challenged. This paper investigates a theoretical model of a polarization imaging system with obliquely incident light and establishes a polarization imaging transmission model with a large field of obliquely incident light. In an imaging experiment with an integrating sphere light source and rotatable polarizer, the polarization imaging transmission model is verified and analysed for two cases of natural light and linearly polarized light incidence. Although the results indicate that the theoretical model is consistent with the experimental results, the theoretical model distinctly differs from the traditional paraxial approximation model. The results prove the accuracy and necessity of the theoretical model and the theoretical guiding significance for theoretical and systematic research of large field polarization imaging.

  3. Differential response to circularly polarized light by the jewel scarab beetle Chrysina gloriosa.

    Science.gov (United States)

    Brady, Parrish; Cummings, Molly

    2010-05-01

    Circularly polarized light is rare in the terrestrial environment, and cuticular reflections from scarab beetles are one of the few natural sources. Chrysina gloriosa LeConte 1854, a scarab beetle found in montane juniper forests of the extreme southwestern United States and northern Mexico, are camouflaged in juniper foliage; however, when viewed with right circularly polarizing filters, the beetles exhibit a stark black contrast. Given the polarization-specific changes in the appearance of C. gloriosa, we hypothesized that C. gloriosa can detect circularly polarized light. We tested for phototactic response and differential flight orientation of C. gloriosa toward different light stimuli. Chrysina gloriosa exhibited (a) positive phototaxis, (b) differential flight orientation between linear and circularly polarized light stimuli of equal intensities, and (c) discrimination between circularly polarized and unpolarized lights of different intensities consistent with a model of circular polarization sensitivity based on a quarter-wave plate. These results demonstrate that C. gloriosa beetles respond differentially to circularly polarized light. In contrast, Chrysina woodi Horn 1885, a close relative with reduced circularly polarized reflection, exhibited no phototactic discrimination between linear and circularly polarized light. Circularly polarized sensitivity may allow C. gloriosa to perceive and communicate with conspecifics that remain cryptic to predators, reducing indirect costs of communication.

  4. Ultraviolet Light Provides a Major Input to Non-Image-Forming Light Detection in Mice

    Science.gov (United States)

    van Oosterhout, Floor; Fisher, Simon P.; van Diepen, Hester C.; Watson, Thomas S.; Houben, Thijs; VanderLeest, Henk Tjebbe; Thompson, Stewart; Peirson, Stuart N.; Foster, Russell G.; Meijer, Johanna H.

    2012-01-01

    Summary The change in irradiance at dawn and dusk provides the primary cue for the entrainment of the mammalian circadian pacemaker. Irradiance detection has been ascribed largely to melanopsin-based phototransduction [1–5]. Here we examine the role of ultraviolet-sensitive (UVS) cones in the modulation of circadian behavior, sleep, and suprachiasmatic nucleus (SCN) electrical activity. UV light exposure leads to phase-shifting responses comparable to those of white light. Moreover, UV light exposure induces sleep in wild-type and melanopsin-deficient (Opn4−/−) mice with equal efficacy. Electrical recordings from the SCN of wild-type mice show that UV light elicits irradiance-dependent sustained responses that are similar to those induced by white light, with characteristic fast transient components occurring at the light transitions. These responses are retained in Opn4−/− mice and preserved under saturating photopic conditions. The sensitivity of phase-shifting responses to UV light is unaffected by the loss of rods but is severely attenuated by the additional loss of cones. Our data show that UVS cones play an important role in circadian and sleep regulation in mice. PMID:22771039

  5. Angular structure of light polarization and singularities in transmittance of nematic liquid crystal cells

    Science.gov (United States)

    Kiselev, Alexei D.; Vovk, Roman G.; Buinyi, Igor O.; Soskin, Marat S.

    2007-06-01

    We study the angular structure of polarization of light transmitted through a nematic liquid crystal (NLC) cell by analyzing the polarization state as a function of the incidence angles. Our theoretical results are obtained by evaluating the Stokes parameters that characterize the polarization state of plane waves propagating through the NLC layer at varying direction of incidence. Using the Stokes polarimetry technique we carried out the measurements of the polarization resolved conoscopic patterns emerging after the homeotropically aligned NLC cell illuminated by the convergent light beam. The resulting polarization resolved angular patterns are described both theoretically and experimentally in terms of the polarization singularities such as C-points (points of circular polarization) and L-lines (lines of linear polarization). When the ellipticity of the incident light varies, the angular patterns are found to undergo transformations involving the processes of creation and annihilation of the C-points.

  6. Polarization-resolved angular patterns of nematic liquid crystal cells: Topological events driven by incident light polarization

    Science.gov (United States)

    Kiselev, Alexei D.; Vovk, Roman G.; Egorov, Roman I.; Chigrinov, Vladimir G.

    2008-09-01

    We study the angular structure of polarization of light transmitted through a nematic liquid crystal (NLC) cell by analyzing the polarization state as a function of the incidence angles and the polarization of the incident wave. The polarization-resolved angular (conoscopic) patterns emerging after the NLC cell illuminated by the convergent light beam are described in terms of the polarization singularities such as C points (points of circular polarization) and L lines (lines of linear polarization). For the homeotropically aligned cell, the Stokes polarimetry technique is used to measure the polarization resolved conoscopic patterns at different values of the ellipticity of the incident light, γell(inc) , impinging onto the cell. Using the exact analytical expressions for the transfer matrix we show that variations of the ellipticity, γell(inc) , induce transformations of the angular pattern exhibiting the effect of avoided L -line crossings and characterized by topological events such as creation and annihilation of the C points. The predictions of the theory are found to be in good agreement with the experimental results.

  7. Slim planar apparatus for converting LED light into collimated polarized light uniformly emitted from its top surface.

    Science.gov (United States)

    Teng, Tun-Chien; Tseng, Li-Wei

    2014-10-20

    This study proposes a slim planar apparatus for converting nonpolarized light from a light-emitting diode (LED) into an ultra-collimated linearly polarized beam uniformly emitted from its top surface. The apparatus was designed based on a folded-bilayer configuration comprising a light-mixing collimation element, polarization conversion element, and polarization-preserving light guide plate (PPLGP) with an overall thickness of 5 mm. Moreover, the apparatus can be extended transversally by connecting multiple light-mixing collimation elements and polarization conversion elements in a side-by-side configuration to share a considerably wider PPLGP, so the apparatus can have theoretically unlimited width. The simulation results indicate that the proposed apparatus is feasible for the maximal backlight modules in 39-inch liquid crystal panels. In the case of an apparatus with a 480 × 80 mm emission area and two 8-lumen LED light sources, the average head-on polarized luminance and spatial uniformity over the emission area was 5000 nit and 83%, respectively; the vertical and transverse angular distributions of the emitting light were only 5° and 10°, respectively. Moreover, the average degree of polarization and energy efficiency of the apparatus were 82% and 72%, respectively. As compared with the high-performance ultra-collimated nonpolarized backlight module proposed in our prior work, not only did the apparatus exhibit outstanding optical performance, but also the highly polarized light emissions actually increased the energy efficiency by 100%.

  8. Material and device studies for the development of ultra-violet light emitting diodes (UV-LEDS) along polar, non-polar and semi-polar directions

    Science.gov (United States)

    Chandrasekaran, Ramya

    Over the past few years, significant effort was dedicated to the development of ultraviolet light emitting diodes (UV-LEDs) for a variety of applications. Such applications include chemical and biological detection, water purification and solid-state lighting. III-Nitride LEDs based on multiple quantum wells (MQWs) grown along the conventional [0001] (polar) direction suffer from the quantum confined Stark effect (QCSE), due to the existence of strong electric fields that arise from spontaneous and piezoelectric polarization. Thus, there is strong motivation to develop MQW-based III-nitride LED structures grown along non-polar and semi-polar directions. The goal of this dissertation is to develop UV-LEDs along the [0001] polar and [11 2¯ 0] non-polar directions by the method of Molecular Beam Epitaxy (MBE). The polar and non-polar LEDs were grown on the C-plane and R-plane sapphire substrates respectively. This work is a combination of materials science studies related to the nucleation, growth and n- and p-type doping of III-nitride films on these two substrates, as well as device studies related to fabrication and characterization of UV-LEDs. It was observed that the crystallographic orientation of the III-nitride films grown on R-plane sapphire depends strongly on the kinetic conditions of growth of the Aluminum Nitride (AIN) buffer. Specifically, growth of the AIN buffer under group III-rich conditions leads to nitride films having the (11 2¯ 0) non polar planes parallel to the sapphire surface, while growth of the buffer under nitrogen rich conditions leads to nitride films with the (11 2¯ 6) semi-polar planes parallel to the sapphire surface. The electron concentration and mobility for the films grown along the polar, non-polar and semi-polar directions were investigated. P-type doping of Gallium Nitride (GaN) films grown on the nonpolar (11 2¯ 0) plane do not suffer from polarity inversion and thus the material was doped p-type with a hole concentration

  9. Myth polar light. Why sky bands, herring lightnings, and solar winds fascinate

    International Nuclear Information System (INIS)

    Hunnekuhl, Michael

    2014-01-01

    The actual state of knowledge of the polar-light research is in this illustrated volume as entertainingly as scientific-foundedly presented. The pecularities of pola lights beyond the polar-light zones as for instance in Germany are thematized and the conditions and periods, in which it there occurs, explained. Michael Hunnekuhl succeeds to mediate the fascination and emotion and simultaneously to explain the phenomena according to the latest state of science generally understandably. Which very old interpretations and descriptions are transmitted, which imaginations had men of polar lights long before the science could them explain? Hunnekuhl takes the reader along with into the world of legends and myths around the polar light. An experience report from the deeply snowed up wideness of Lapland lets everybody closely participate at a polar-light observation and feel the emotion, which it can fan. Above 70 polar-light pictures of high value and further explaining graphics show the continuously changing play of colors, supplement the explanations, and make the fascination comprehensible. Spectacular polar-light films from the international space station ISS, photographs from sun-observation satellites, as well as a polar-light film in real time are bound in the book via QR codes and make the time dimension and the dynamics of this fascinating natural spectacle alively comprehensible.

  10. Highly polarized light emission by isotropic quantum dots integrated with magnetically aligned segmented nanowires

    International Nuclear Information System (INIS)

    Uran, Can; Erdem, Talha; Guzelturk, Burak; Perkgöz, Nihan Kosku; Jun, Shinae; Jang, Eunjoo; Demir, Hilmi Volkan

    2014-01-01

    In this work, we demonstrate a proof-of-concept system for generating highly polarized light from colloidal quantum dots (QDs) coupled with magnetically aligned segmented Au/Ni/Au nanowires (NWs). Optical characterizations reveal that the optimized QD-NW coupled structures emit highly polarized light with an s-to p-polarization (s/p) contrast as high as 15:1 corresponding to a degree of polarization of 0.88. These experimental results are supported by the finite-difference time-domain simulations, which demonstrate the interplay between the inter-NW distance and the degree of polarization.

  11. Electrically controlled phases of partially polarized light and orientational Kerr effect in liquid crystal ferroelectrics

    Science.gov (United States)

    Kiselev, Alexei D.; Kesaev, Vladimir V.; Pozhidaev, Evgeny P.

    2017-10-01

    We study the electro-optic properties of subwavelength-pitch deformed-helix ferroelectric liquid crystals illuminated with partially polarized light. In an experimental setup based on the Mach-Zehnder interferometer, it is found that the interference pattern crucially depends on the degree of polarization of the incident light. We evaluate the electric field dependence of both the Pancharatnam relative phase and the geometric phase for the general case of nonunitarily evolving mixed polarization states.

  12. Effect of light source parameters on the polarization properties of the beam

    Science.gov (United States)

    Liu, Dan; Liu, Yan; Jiang, Hui-lin; Liu, Zhi; Zhou, Xin; Fang, Hanhan

    2013-08-01

    Polarized laser has been widely used in free space optical communication, laser radar, and laser ranging system because of its advantages of good performance in recent years. The changes of laser polarization properties in the process of transmission in atmospheric turbulence have a certain impact on the system performance. The paper research on the rule of polarization properties changes of Gauss Schell model beam in turbulent conditions. And analysis the main factors to affect the polarization properties by numerical simulation using MATLAB software tools. The factors mainly including: initial polarization, coherence coefficient, spot size and the intensity of the atmospheric turbulent. The simulation results show that, the degree of polarization will converge to the initial polarization when the beam propagation in turbulent conditions. The degrees of polarization change to different value when initial polarization of beam is different in a short distance. And, the degrees of polarization converge to the initial polarization after long distance. Beam coherence coefficient bigger, the degree of polarization and change range increases bigger. The change of polarization more slowly for spot size is bigger. The change of polarization change is faster for longer wavelength. The conclusion of the study indicated that the light source parameters effect the changes of polarization properties under turbulent conditions. The research provides theory basis for the polarization properties of the laser propagation, and it will plays a significant role in optical communication and target recognition.

  13. Electrical tuning of the polarization state of light using graphene-integrated anisotropic metasurfaces

    Science.gov (United States)

    Dutta-Gupta, Shourya; Dabidian, Nima; Kholmanov, Iskandar; Belkin, Mikhail A.; Shvets, Gennady

    2017-03-01

    Plasmonic metasurfaces have been employed for moulding the flow of transmitted and reflected light, thereby enabling numerous applications that benefit from their ultra-thin sub-wavelength format. Their appeal is further enhanced by the incorporation of active electro-optic elements, paving the way for dynamic control of light's properties. In this paper, we realize a dynamic polarization state generator using a graphene-integrated anisotropic metasurface (GIAM) that converts the linear polarization of the incident light into an elliptical one. This is accomplished by using an anisotropic metasurface with two principal polarization axes, one of which possesses a Fano-type resonance. A gate-controlled single-layer graphene integrated with the metasurface was employed as an electro-optic element controlling the phase and intensity of light polarized along the resonant axis of the GIAM. When the incident light is polarized at an angle to the resonant axis of the metasurface, the ellipticity of the reflected light can be dynamically controlled by the application of a gate voltage. Thus accomplished dynamic polarization control is experimentally demonstrated and characterized by measuring the Stokes polarization parameters. Large changes of the ellipticity and the tilt angle of the polarization ellipse are observed. Our measurements show that the tilt angle can be changed from positive values through zero to negative values while keeping the ellipticity constant, potentially paving the way to rapid ellipsometry and other characterization techniques requiring fast polarization shifting. This article is part of the themed issue 'New horizons for nanophotonics'.

  14. Morning and Evening Oscillators Cooperate to Reset Circadian Behavior in Response to Light Input

    Directory of Open Access Journals (Sweden)

    Pallavi Lamba

    2014-05-01

    Full Text Available Light is a crucial input for circadian clocks. In Drosophila, short light exposure can robustly shift the phase of circadian behavior. The model for this resetting posits that circadian photoreception is cell autonomous: CRYPTOCHROME senses light, binds to TIMELESS (TIM, and promotes its degradation, which is mediated by JETLAG (JET. However, it was recently proposed that interactions between circadian neurons are also required for phase resetting. We identify two groups of neurons critical for circadian photoreception: the morning (M and the evening (E oscillators. These neurons work synergistically to reset rhythmic behavior. JET promotes acute TIM degradation cell autonomously in M and E oscillators but also nonautonomously in E oscillators when expressed in M oscillators. Thus, upon light exposure, the M oscillators communicate with the E oscillators. Because the M oscillators drive circadian behavior, they must also receive inputs from the E oscillators. Hence, although photic TIM degradation is largely cell autonomous, neural cooperation between M and E oscillators is critical for circadian behavioral photoresponses.

  15. Measurements of polarization-dependent angle-resolved light scattering from individual microscopic samples using Fourier transform light scattering

    Science.gov (United States)

    Jung, JaeHwang; Kim, Jinhyung; Seo, Min-Kyo; Park, YongKeun

    2018-03-01

    We present a method to measure the vector-field light scattering of individual microscopic objects. The polarization-dependent optical field images are measured with quantitative phase imaging at the sample plane, and then numerically propagated to the far-field plane. This approach allows the two-dimensional polarization-dependent angle-resolved light scattered patterns from individual object to be obtained with high precision and sensitivity. Using this method, we present the measurements of the polarization-dependent light scattering of a liquid crystal droplet and individual silver nanowires over scattering angles of 50{\\deg}. In addition, the spectroscopic extension of the polarization-dependent angle-resolved light scattering is demonstrated using wavelength-scanning illumination.

  16. Manipulating light polarizations with a hyperbolic metamaterial waveguide.

    Science.gov (United States)

    Zhu, Hua; Yin, Xiang; Chen, Lin; Zhu, Zhongshu; Li, Xun

    2015-10-15

    In this Letter we demonstrate that a hyperbolic metamaterial (HMM) waveguide array exhibits a giant modal birefringence between the TE and TM modes by utilization of a rectangular waveguide cross section. We further reveal that the designed polarization manipulation device using such a HMM waveguide array with a subwavelength thickness presents the ability to function as a polarizer or quarter- or half-wave plate that enables transmission only for electromagnetic wave (EW) that is polarized at a specific direction, or converting linearly polarized EW to circularly and elliptically polarized EW or rotating linearly polarized EW with 90° at terahertz (THz) frequencies. A giant modal birefringence between the TE and TM modes from 0.8 to 2 between 2 and 4.8 THz is achievable, which is dozens of times higher than conventional quartz birefringent crystals for THz waves. This polarization manipulation device has the performance merits including high transmission efficiency, ultra-compactness, and tunable birefringence, offering a promising approach to manipulating the polarization states of EW.

  17. Light polarization management via reflection from arrays of sub-wavelength metallic twisted bands

    Science.gov (United States)

    Nawrot, M.; Haberko, J.; Zinkiewicz, Ł.; Wasylczyk, P.

    2017-12-01

    With constant progress of nano- and microfabrication technologies, photolithography in particular, a number of sub-wavelength metallic structures have been demonstrated that can be used to manipulate light polarization. Numerical simulations of light propagation hint that helical twisted bands can have interesting polarization properties. We use three-dimensional two-photon photolithography (direct laser writing) to fabricate a few-micrometer-thick arrays of twisted bands and coat them uniformly with metal. We demonstrate that circular polarization can be generated from linear polarization upon reflection from such structures over a broad range of frequencies in the mid infrared.

  18. Light in condensed matter in the upper atmosphere as the origin of homochirality: circularly polarized light from Rydberg matter.

    Science.gov (United States)

    Holmlid, Leif

    2009-01-01

    Clouds of the condensed excited Rydberg matter (RM) exist in the atmospheres of comets and planetary bodies (most easily observed at Mercury and the Moon), where they surround the entire bodies. Vast such clouds are recently proposed to exist in the upper atmosphere of Earth (giving rise to the enormous features called noctilucent clouds, polar mesospheric clouds, and polar mesospheric summer radar echoes). It has been shown in experiments with RM that linearly polarized visible light scattered from an RM layer is transformed to circularly polarized light with a probability of approximately 50%. The circular Rydberg electrons in the magnetic field in the RM may be chiral scatterers. The magnetic and anisotropic RM medium acts as a circular polarizer probably by delaying one of the perpendicular components of the light wave. The delay process involved is called Rabi-flopping and gives delays of the order of femtoseconds. This strong effect thus gives intense circularly polarized visible and UV light within RM clouds. Amino acids and other chiral molecules will experience a strong interaction with this light field in the upper atmospheres of planets. The interaction will vary with the stereogenic conformation of the molecules and in all probability promote the survival of one enantiomer. Here, this strong effect is proposed to be the origin of homochirality. The formation of amino acids in the RM clouds is probably facilitated by the catalytic effect of RM.

  19. Experimental demonstration of multiple-inputs multiple-outputs OFDM/OQAM visible light communications

    Science.gov (United States)

    Lin, Bangjiang; Tang, Xuan; Ghassemlooy, Zabih; Lin, Chun; Zhang, Min

    2017-10-01

    We experimentally demonstrate a 2×2 optical multiple-inputs multiple-outputs (MIMO) visible light communications system based on the modified orthogonal frequency-division multiplexing/offset quadrature amplitude modulation scheme. The adjacent subcarrier frequency-domain averaging (ASFA) with the full-loaded (FL) and half-loaded (HL) preamble structures is proposed for demultiplexing and mitigating the intrinsic imaginary interference (IMI) effect. Compared with the conventional channel estimation (CE) method, ASFA offers improved transmission performance. With the FL method, we obtain more accurate MIMO CE to mitigate the IMI effect and the optical noise compared to the HL method.

  20. Study of double-ring slow-light gyroscope with two input-output waveguides

    Science.gov (United States)

    Gu, Hong; Liu, Xiao-qing

    2017-10-01

    A novel structure of double-ring slow-light gyroscope with two input-output waveguides is studied. We utilize interferometric detection method, and sufficiently combine the advantages of Interferometric Fiber Optic Gyro (I-FOG) and Resonator Optic Gyro (ROG). The responses of the structure are derived and simulated. Here two experimental schemes are also proposed. By applying a square wave to the integrated phase modulator, we can make the structure work at the highest sensitivity. After applied the square wave, the system runs at linear zone, thus the angular velocity can be obtained according to the linear relationship between the phase difference and the angular velocity. The optimal parameters for the largest phase difference of light signal monitored at different output ports are investigated. Some comparisons are done in the condition of various values of transmission loss coefficients.

  1. Optical asymmetric cryptography based on amplitude reconstruction of elliptically polarized light

    Science.gov (United States)

    Cai, Jianjun; Shen, Xueju; Lei, Ming

    2017-11-01

    We propose a novel optical asymmetric image encryption method based on amplitude reconstruction of elliptically polarized light, which is free from silhouette problem. The original image is analytically separated into two phase-only masks firstly, and then the two masks are encoded into amplitudes of the orthogonal polarization components of an elliptically polarized light. Finally, the elliptically polarized light propagates through a linear polarizer, and the output intensity distribution is recorded by a CCD camera to obtain the ciphertext. The whole encryption procedure could be implemented by using commonly used optical elements, and it combines diffusion process and confusion process. As a result, the proposed method achieves high robustness against iterative-algorithm-based attacks. Simulation results are presented to prove the validity of the proposed cryptography.

  2. Theoretical model of a polarization diffractive elements for the light beams conversion holographic formation in PDLCs

    Science.gov (United States)

    Sharangovich, Sergey N.; Semkin, Artem O.

    2017-12-01

    In this work a theoretical model of the holographic formation of the polarization diffractive optical elements for the transformation of Gaussian light beams into Bessel-like ones in polymer-dispersed liquid crystals (PDLC) is developed. The model is based on solving the equations of photo-induced Fredericks transition processes for polarization diffractive elements formation by orthogonally polarized light beams with inhomogeneous amplitude and phase profiles. The results of numerical simulation of the material's dielectric tensor changing due to the structure's formation process are presented for various recording beams' polarization states. Based on the results of numerical simulation, the ability to form the diffractive optical elements for light beams transformation by the polarization holography methods is shown.

  3. A novel autonomous real-time position method based on polarized light and geomagnetic field.

    Science.gov (United States)

    Wang, Yinlong; Chu, Jinkui; Zhang, Ran; Wang, Lu; Wang, Zhiwen

    2015-04-08

    Many animals exploit polarized light in order to calibrate their magnetic compasses for navigation. For example, some birds are equipped with biological magnetic and celestial compasses enabling them to migrate between the Western and Eastern Hemispheres. The Vikings' ability to derive true direction from polarized light is also widely accepted. However, their amazing navigational capabilities are still not completely clear. Inspired by birds' and Vikings' ancient navigational skills. Here we present a combined real-time position method based on the use of polarized light and geomagnetic field. The new method works independently of any artificial signal source with no accumulation of errors and can obtain the position and the orientation directly. The novel device simply consists of two polarized light sensors, a 3-axis compass and a computer. The field experiments demonstrate device performance.

  4. Central-moment description of polarization for quantum states of light

    DEFF Research Database (Denmark)

    Björk, G.; Söderholm, J.; Kim, Y.-S.

    2012-01-01

    We present a moment expansion for the systematic characterization of the polarization properties of quantum states of light. Specifically,we link the method to themeasurements of the Stokes operator in different directions on the Poincar´e sphere and provide a scheme for polarization tomography w...

  5. Investigation of the state of polarization of light in a single-mode fiber waveguide

    Science.gov (United States)

    Kozel, S. M.; Kreopalov, V. I.; Listvin, V. N.; Glavatskikh, N. A.

    1983-01-01

    An analysis is made of the polarization anisotropy of a single-mode fiber with a twisted elliptic core. The Jones matrix is obtained and the complex function of the state of polarization of light in a fiber is investigated. The results are reported of measurements of the linear and circular birefringence of a borosilicate single-mode glass fiber.

  6. Depth enhancement of multi-layer light field display using polarization dependent internal reflection.

    Science.gov (United States)

    Jo, Na-Young; Lim, Hong-Gi; Lee, Sung-Keun; Kim, Yong-Soo; Park, Jae-Hyeung

    2013-12-02

    A technique to enhance the depth range of the multi-layer light field three-dimensional display is proposed. A set of the optical plates are stacked in front of the conventional multi-layer light field display, creating additional internal reflection for one polarization state. By switching between two orthogonal polarization states in synchronization with the displayed three-dimensional images, the depth range of the display can be doubled. The proposed method is verified experimentally, confirming its feasibility.

  7. Photoemission of Bi_{2}Se_{3} with Circularly Polarized Light: Probe of Spin Polarization or Means for Spin Manipulation?

    Directory of Open Access Journals (Sweden)

    J. Sánchez-Barriga

    2014-03-01

    Full Text Available Topological insulators are characterized by Dirac-cone surface states with electron spins locked perpendicular to their linear momenta. Recent theoretical and experimental work implied that this specific spin texture should enable control of photoelectron spins by circularly polarized light. However, these reports questioned the so far accepted interpretation of spin-resolved photoelectron spectroscopy. We solve this puzzle and show that vacuum ultraviolet photons (50–70 eV with linear or circular polarization indeed probe the initial-state spin texture of Bi_{2}Se_{3} while circularly polarized 6-eV low-energy photons flip the electron spins out of plane and reverse their spin polarization, with its sign determined by the light helicity. Our photoemission calculations, taking into account the interplay between the varying probing depth, dipole-selection rules, and spin-dependent scattering effects involving initial and final states, explain these findings and reveal proper conditions for light-induced spin manipulation. Our results pave the way for future applications of topological insulators in optospintronic devices.

  8. Managing light polarization via plasmon-molecule interactions within an asymmetric metal nanoparticle trimer

    International Nuclear Information System (INIS)

    Shegai, Timur; Li, Zhipeng; Zhang, Zhenyu; Xu, Hongxing; Haran, Gilad

    2008-01-01

    The interaction of light with metal nanoparticles leads to novel phenomena mediated by surface plasmon excitations. In this paper we use single molecules to characterize the interaction of surface plasmons with light, and show that such interaction can strongly modulate the polarization of the emitted light. The simplest nanostructures that enable such polarization modulation are asymmetric silver nanocrystal trimers, where individual Raman scattering molecules are located in the gap between two of the nanoparticles. The third particle breaks the dipolar symmetry of the two-particle junction, generating a wavelength-dependent polarization pattern. Indeed, the scattered light becomes elliptically polarized and its intensity pattern is rotated in the presence of the third particle. We use a combination of spectroscopic observations on single molecules, scanning electron microscope imaging, and generalized Mie theory calculations to provide a full picture of the effect of particles on the polarization of the emitted light. Furthermore, our theoretical analysis allows us to show that the observed phenomenon is very sensitive to the size of the trimer particles and their relative position, suggesting future means for precise control of light polarization on the nanoscale.

  9. Can invertebrates see the e-vector of polarization as a separate modality of light?

    Science.gov (United States)

    Labhart, Thomas

    2016-12-15

    The visual world is rich in linearly polarized light stimuli, which are hidden from the human eye. But many invertebrate species make use of polarized light as a source of valuable visual information. However, exploiting light polarization does not necessarily imply that the electric (e)-vector orientation of polarized light can be perceived as a separate modality of light. In this Review, I address the question of whether invertebrates can detect specific e-vector orientations in a manner similar to that of humans perceiving spectral stimuli as specific hues. To analyze e-vector orientation, the signals of at least three polarization-sensitive sensors (analyzer channels) with different e-vector tuning axes must be compared. The object-based, imaging polarization vision systems of cephalopods and crustaceans, as well as the water-surface detectors of flying backswimmers, use just two analyzer channels. Although this excludes the perception of specific e-vector orientations, a two-channel system does provide a coarse, categoric analysis of polarized light stimuli, comparable to the limited color sense of dichromatic, 'color-blind' humans. The celestial compass of insects employs three or more analyzer channels. However, that compass is multimodal, i.e. e-vector information merges with directional information from other celestial cues, such as the solar azimuth and the spectral gradient in the sky, masking e-vector information. It seems that invertebrate organisms take no interest in the polarization details of visual stimuli, but polarization vision grants more practical benefits, such as improved object detection and visual communication for cephalopods and crustaceans, compass readings to traveling insects, or the alert 'water below!' to water-seeking bugs. © 2016. Published by The Company of Biologists Ltd.

  10. Polarization Optics

    OpenAIRE

    Fressengeas, Nicolas

    2010-01-01

    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  11. [Impact of Light Polarization on the Measurement of Water Particulate Backscattering Coefficient].

    Science.gov (United States)

    Liu, Jia; Gong, Fang; He, Xian-qiang; Zhu, Qian-kun; Huang, Hai-qing

    2016-01-01

    Particulate backscattering coefficient is a main inherent optical properties (IOPs) of water, which is also a determining factor of ocean color and a basic parameter for inversion of satellite ocean color remote sensing. In-situ measurement with optical instruments is currently the main method for obtaining the particulate backscattering coefficient of water. Due to reflection and refraction by the mirrors in the instrument optical path, the emergent light source from the instrument may be partly polarized, thus to impact the measurement accuracy of water backscattering coefficient. At present, the light polarization of measuring instruments and its impact on the measurement accuracy of particulate backscattering coefficient are still poorly known. For this reason, taking a widely used backscattering coefficient measuring instrument HydroScat6 (HS-6) as an example in this paper, the polarization characteristic of the emergent light from the instrument was systematically measured, and further experimental study on the impact of the light polarization on the measurement accuracy of the particulate backscattering coefficient of water was carried out. The results show that the degree of polarization(DOP) of the central wavelength of emergent light ranges from 20% to 30% for all of the six channels of the HS-6, except the 590 nm channel from which the DOP of the emergent light is slightly low (-15%). Therefore, the emergent light from the HS-6 has significant polarization. Light polarization has non-neglectable impact on the measurement of particulate backscattering coefficient, and the impact degree varies with the wave band, linear polarization angle and suspended particulate matter (SPM) concentration. At different SPM concentrations, the mean difference caused by light polarization can reach 15.49%, 11.27%, 12.79%, 14.43%, 13.76%, and 12.46% in six bands, 420, 442, 470, 510, 590, and 670 nm, respectively. Consequently, the impact of light polarization on the

  12. Light-induced spin polarizations in quantum rings

    NARCIS (Netherlands)

    Joibari, F.K.; Blanter, Y.M.; Bauer, G.E.W.

    2014-01-01

    Nonresonant circularly polarized electromagnetic radiation can exert torques on magnetizations by the inverse Faraday effect (IFE). Here, we discuss the enhancement of IFE by spin-orbit interactions. We illustrate the principle by studying a simple generic model system, i.e., the

  13. Planetary systems in polarized light: Debris disk observations and instrumentation

    Science.gov (United States)

    Millar-Blanchaer, Maxwell A.

    Understanding planet formation is one of the major challenges of modern astronomy. Polarimetry is a powerful tool with which we can confront this challenge. In particular, polarimetric observations can be useful for imaging debris disks and characterizing exoplanet atmospheres. With that in mind, this thesis has been constructed with two main aspects: i) observational studies of two debris disk systems, beta Pic and HD 157587, using the Gemini Planet Imager and ii) the characterization and testing of a new type of diffraction grating, called a polarization grating, that we plan to use for future observations of exoplanet atmospheres. The Gemini Planet Imager is a high-contrast imager that includes a polarimetry mode designed to image circumstellar disks. Here we detail the development of new data analysis techniques that reduce systematics and noise in processed GPI data. We apply these techniques to observations of the beta Pic and HD 157587 debris disks and then fit each disk image to a geometric disk model. The beta Pic disk model's morphology cannot be explained by interactions with the planet beta Pic b, and the presence of a second planet could be invoked to explain the discrepancy. In the case of HD 157587, the disk model's geometric centre is offset from the location of the star, which could be explained by a perturbing planet. Characterization of the planets' interactions with their debris disks is a critical method to gain more information about these two systems. The second component of this thesis focuses on polarization gratings, thin film optical devices that can simultaneously act as polarizing beam splitters and as spectral dispersive elements. Moreover, they can be designed for high diffraction efficiency across a broad wavelength range. These features make polarization gratings useful for many types of astronomical observations. We have carried out laboratory and on-sky test observations using a polarization grating optimized for visible

  14. The HIP 79977 debris disk in polarized light

    Science.gov (United States)

    Engler, N.; Schmid, H. M.; Thalmann, Ch.; Boccaletti, A.; Bazzon, A.; Baruffolo, A.; Beuzit, J. L.; Claudi, R.; Costille, A.; Desidera, S.; Dohlen, K.; Dominik, C.; Feldt, M.; Fusco, T.; Ginski, C.; Gisler, D.; Girard, J. H.; Gratton, R.; Henning, T.; Hubin, N.; Janson, M.; Kasper, M.; Kral, Q.; Langlois, M.; Lagadec, E.; Ménard, F.; Meyer, M. R.; Milli, J.; Mouillet, D.; Olofsson, J.; Pavlov, A.; Pragt, J.; Puget, P.; Quanz, S. P.; Roelfsema, R.; Salasnich, B.; Siebenmorgen, R.; Sissa, E.; Suarez, M.; Szulagyi, J.; Turatto, M.; Udry, S.; Wildi, F.

    2017-11-01

    Context. Debris disks are observed around 10 to 20% of FGK main-sequence stars as infrared excess emission. They are important signposts for the presence of colliding planetesimals and therefore provide important information about the evolution of planetary systems. Direct imaging of such disks reveals their geometric structure and constrains their dust-particle properties. Aims: We present observations of the known edge-on debris disk around HIP 79977 (HD 146897) taken with the ZIMPOL differential polarimeter of the SPHERE instrument. We measure the observed polarization signal and investigate the diagnostic potential of such data with model simulations. Methods: SPHERE-ZIMPOL polarimetric data of the 15 Myr-old F star HIP 79977 (Upper Sco, 123 pc) were taken in the Very Broad Band (VBB) filter (λc = 735 nm, Δλ = 290 nm) with a spatial resolution of about 25 mas. Imaging polarimetry efficiently suppresses the residual speckle noise from the AO system and provides a differential signal with relatively small systematic measuring uncertainties. We measure the polarization flux along and perpendicular to the disk spine of the highly inclined disk for projected separations between 0.2'' (25 AU) and 1.6'' (200 AU). We perform model calculations for the polarized flux of an optically thin debris disk which are used to determine or constrain the disk parameters of HIP 79977. Results: We measure a polarized flux contrast ratio for the disk of (Fpol)disk/F∗ = (5.5 ± 0.9) × 10-4 in the VBB filter. The surface brightness of the polarized flux reaches a maximum of SBmax = 16.2 mag arcsec-2 at a separation of 0.2''-0.5'' along the disk spine with a maximum surface brightness contrast of 7.64 mag arcsec-2. The polarized flux has a minimum near the star 1''. This can be explained by a radial blow-out of small grains. The data are modelled as a circular dust belt with a well defined disk inclination I = 85( ± 1.5)° and a radius between r0 = 60 and 90 AU. The radial

  15. Circularly polarized light emission in scanning tunneling microscopy of magnetic systems

    International Nuclear Information System (INIS)

    Apell, S.P.; Penn, D.R.; Johansson, P.

    2000-01-01

    Light is produced when a scanning tunneling microscope is used to probe a metal surface. Recent experiments on cobalt utilizing a tungsten tip found that the light is circularly polarized; the sense of circular polarization depends on the direction of the sample magnetization, and the degree of polarization is of order 10%. This raises the possibility of constructing a magnetic microscope with very good spatial resolution. We present a theory of this effect for iron and cobalt and find a degree of polarization of order 0.1%. This is in disagreement with the experiments on cobalt as well as previous theoretical work which found order of magnitude agreement with the experimental results. However, a recent experiment on iron showed 0.0±2%. We predict that the use of a silver tip would increase the degree of circular polarization for a range of photon energies

  16. Retrieving the polarization information for satellite-to-ground light communication

    International Nuclear Information System (INIS)

    Tao, Qiangqiang; Guo, Zhongyi; Xu, Qiang; Gao, Jun; Jiao, Weiyan; Wang, Xinshun; Qu, Shiliang

    2015-01-01

    In this paper, we have investigated the reconstruction of the polarization states (degree of polarization (DoP) and angle of polarization (AoP)) of the incident light which passed through a 10 km atmospheric medium between the satellite and the Earth. Here, we proposed a more practical atmospheric model in which the 10 km atmospheric medium is divided into ten layers to be appropriate for the Monte Carlo simulation algorithm. Based on this model, the polarization retrieve (PR) method can be used for reconstructing the initial polarization information effectively, and the simulated results demonstrate that the mean errors of the retrieved DoP and AoP are very close to zero. Moreover, the results also show that although the atmospheric medium system is fixed, the Mueller matrices for the downlink and uplink are completely different, which shows that the light transmissions in the two links are irreversible in the layered atmospheric medium system. (paper)

  17. Circularly polarized light interaction in topological insulators investigated by time-resolved ARPES

    Science.gov (United States)

    Bugini, D.; Hedayat, H.; Boschini, F.; Yi, H.; Chen, C.; Zhou, X.; Manzoni, C.; Dallera, C.; Cerullo, G.; Carpene, E.

    2017-10-01

    Topological Insulators (TI) represent a hot-topic for both basic physics and promising applications because of the in-plane spin-polarized surface states (TSS) arising within the bulk insulating energy gap. The backscattering protection and the control of the spin polarization using ultrashort light pulses open new scenarios in the use of this class of materials for future opto-spintronic devices. Using time- and angle-resolved photoemission spectroscopy on Sb x Bi(2‑x )Se y Te(3‑y ) class we studied the response of spin-polarized electrons to ultrashort circularly-polarized pulses. Here, we report for the first time the experimental evidence of a direct coupling between light and empty topological surface states (ESS) and the establishment of a flow of spin-polarized electrons in k-space i.e. a photon-induced spin-current.

  18. What makes single-helical metamaterials generate "pure" circularly polarized light?

    Science.gov (United States)

    Wu, Lin; Yang, ZhenYu; Zhao, Ming; Zhang, Peng; Lu, ZeQing; Yu, Yang; Li, ShengXi; Yuan, XiuHua

    2012-01-16

    Circular polarizers with left-handed helical metamaterials can transmit right-handed circularly polarized (RCP) light with few losses. But a certain amount of left-handed circularly polarized (LCP) light will occur in the transmitted light, which is the noise of the circular polarizer. Therefore, we defined the ratio of the RCP light intensity to the LCP light intensity as the signal-to-noise (S/N) ratio. In our previous work, it's found that circular polarizers with multi-helical metamaterials have two orders higher S/N ratios than that of single-helical metamaterials. However, it has been a great challenge to fabricate such multi-helical structures with micron or sub-micron feature sizes. Is it possible for the single-helical metamaterials to obtain equally high S/N ratios as the multi-helical ones? To answer this question, we systematically investigated the influences of structure parameters of single-helical metamaterials on the S/N ratios using the finite-different time-domain (FDTD) method. It was found that the single-helical metamaterials can also reach about 30dB S/N ratios, which are equal to the multi-helical ones. Furthermore, we explained the phenomenon by the antenna theory and optimized the performances of the single-helical circular polarizers.

  19. Selective Deflection of Polarized Light Via Coherently Driven Four-Level Atoms in a Double-Λ Configuration

    International Nuclear Information System (INIS)

    Guo Yu

    2010-01-01

    We study the interaction of a weak probe field, having two circular polarized components, i.e., σ - and σ + polarization, with an optically dense medium of four-level atoms in a double-Λ configuration, which is mediated by the electromagnetically induced transparency with a polarized control light with spatially inhomogeneous profile. We analyse the deflection of the polarized probe light and we find that we can selectively determine which circular component will be deflected after the polarized probe light enters the atom medium via adjusting the polarization and detuning of the control field. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  20. Field spectrometer measurement errors in presence of partially polarized light; evaluation of ground truth measurement accuracy.

    Science.gov (United States)

    Lévesque, Martin P; Dissanska, Maria

    2016-11-28

    Considering that natural light is always partially polarized (reflection, Rayleigh scattering, etc.) and the alteration of the spectral response of spectrometers due to the polarization, some concerns were raised about the accuracy and variability of spectrometer outdoor measurements in field campaigns. We demonstrated by simple experiments that, in some circumstances, spectral measurements can be affected by the polarization. The signal variability due to polarization sensitivity of the spectrometer for the measured sample was about 5-10%. We noted that, measuring surfaces at right angle (a frequently used measurement protocol) minimized the problems due to polarization, producing valid results. On the other hand, measurements acquired with a slant angle are more or less accurate; an important proportion of the signal variability is due to the polarization. Direct sun reflection and reflection from close objects must be avoided.

  1. A test of the equivalence principle with polarized light

    International Nuclear Information System (INIS)

    Lesche, B.; Bedran, M.L.

    1987-01-01

    The behaviour of electromagnetic radiation in the Schwarzschild metric of the sun is studied with the presence of a non-minimal coupling term of electromagnetism and gravity. An anomalous deflection is predicted, as well as a polarization effect. These effects can be used to obtain experimental upper bounds for the coupling constant of the non-minimal coupling. The strength of these upper bounds is discussed. (author) [pt

  2. Polarized light scattering as a probe for changes in chromosome structure

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, Daniel Benjamin [Univ. of California, Berkeley, CA (United States)

    1993-10-01

    Measurements and calculations of polarized light scattering are applied to chromosomes. Calculations of the Mueller matrix, which completely describes how the polarization state of light is altered upon scattering, are developed for helical structures related to that of chromosomes. Measurements of the Mueller matrix are presented for octopus sperm heads, and dinoflagellates. Comparisons of theory and experiment are made. A working theory of polarized light scattering from helices is developed. The use of the first Born approximation vs the coupled dipole approximation are investigated. A comparison of continuous, calculated in this work, and discrete models is also discussed. By comparing light scattering measurements with theoretical predictions the average orientation of DNA in an octopus sperm head is determined. Calculations are made for the Mueller matrix of DNA plectonemic helices at UV, visible and X-ray wavelengths. Finally evidence is presented that the chromosomes of dinoflagellates are responsible for observed differential scattering of circularly-polarized light. This differential scattering is found to vary in a manner that is possibly correlated to the cell cycle of the dinoflagellates. It is concluded that by properly choosing the wavelength probe polarized light scattering can provide a useful tool to study chromosome structure.

  3. Dynamically Switching the Polarization State of Light Based on the Phase Transition of Vanadium Dioxide

    Science.gov (United States)

    Jia, Zhi-Yong; Shu, Fang-Zhou; Gao, Ya-Jun; Cheng, Feng; Peng, Ru-Wen; Fan, Ren-Hao; Liu, Yongmin; Wang, Mu

    2018-03-01

    There have been great endeavors devoted to manipulating the polarization state of light by plasmonic nanostructures in recent decades. However, the topic of active polarizers has attracted much less attention. We present a composite plasmonic nanostructure consisting of vanadium dioxide that can dynamically modulate the polarization state of the reflected light through a thermally induced phase transition of vanadium dioxide. We design a system consisting of anisotropic plasmonic nanostructures with vanadium dioxide that exhibits distinct reflections subjected to different linearly polarized incidence at room temperature and in the heated state. Under a particular linearly polarized incidence, the polarization state of the reflected light changes at room temperature, and reverts to its original polarization state above the phase-transition temperature. The composite structure can also be used to realize a dynamically switchable infrared image, wherein a pattern can be visualized at room temperature while it disappears above the phase-transition temperature. The composite structure could be potentially used for versatile optical modulators, molecular detection, and polarimetric imaging.

  4. Dinosaur demise in light of their alleged perennial polar residency

    Science.gov (United States)

    Lewy, Zeev

    2017-10-01

    The end-Cretaceous biological crisis is represented by the demise of the non-avian dinosaurs. However, most crucial biologically was the elimination of the photosynthesizing marine phyto- and zooplankton forming the base of the marine food chain. Their abrupt demise attests to sunlight screening darkening the atmosphere for a few years. Alvarez et al. (Science 208:1095-1108, 1980. doi: 10.1126/science.208.44) noticed in deep marine end-Cretaceous sediments an anomalous rise in the chemical element iridium (Ir), which is rare on planet Earth and thus suggests an extraterrestrial origin through an impact of a large asteroid. This impact would have ejected enormous quantities of particles and aerosols, shading the solar illumination as attested to by the elimination of the marine photosynthesizing plankton. Such a dark period must have affected life on land. The apparent cold-blooded non-avian dinosaurs, which were used to living in open terrains to absorb the solar illumination, became inactive during the dark period and were incapable of withstanding predators. This was in contrast to cold-blooded crocodilians, turtles and lizards that could hide in refuge sites on land and in the water. Dinosaur relics discovered in Cretaceous Polar Regions were attributed to perennial residents, surviving the nearly half-year-long dark winter despite their ability to leave. The polar concentrations of disarticulated dinosaur bones were suggested as having resulted from a catastrophic burial of a population by floods. However, this should have fossilized complete skeletons. Alternatively, herds of dinosaurs living in high latitudes might have been sexually driven to spend the half year of continuously illuminated polar summer for mating rather than for nourishment, in which the lower latitudes provided as well. The aggressive mating competitions would have left victims among the rivals and of young ones incidentally trampled over, all being consumed and their skeletons

  5. Optically polarized atoms understanding light-atom interactions

    CERN Document Server

    Auzinsh, Marcis; Rochester, Simon M

    2010-01-01

    This book is addressed at upper-level undergraduate and graduate students involved in research in atomic, molecular, and optical Physics. It will also be useful to researchers practising in this field. It gives an intuitive, yet sufficiently detailed and rigorous introduction to light-atom interactions with a particular emphasis on the symmetry aspects of the interaction, especially those associated with the angular momentum of atoms and light. The book will enable readers to carryout practical calculations on their own, and is richly illustrated with examples drawn from current research topic

  6. Extinction of polarized light in ferrofluids with different magnetic particle concentrations

    International Nuclear Information System (INIS)

    Socoliuc, V.; Popescu, L.B.

    2012-01-01

    The magnetic field intensity and nanoparticle concentration dependence of the polarized light extinction in a ferrofluid made of magnetite particles stabilized with technical grade oleic acid dispersed in transformer oil was experimentally investigated. The magnetically induced optical anisotropy, i.e. the dichroism divided by concentration, was found to decrease with increasing sample concentration from 2% to 8%. The magnetically induced change in the optical extinction of light polarized at 54.74 o with respect to the magnetic field direction was found to be positive for the less concentrated sample (2%) and negative for the samples with 4% and 8% magnetic nanoparticle concentrations, the more negative the higher the concentration and field intensity. Based on the theoretically proven fact that the particle orientation mechanism has no effect on the extinction of light polarized at 54.74 o with respect to the field direction, we analyzed the experimental findings in the frames of the agglomeration and long-range pair correlations theories for the magnetically induced optical anisotropy in ferrofluids. We developed a theoretical model in the approximation of single scattering for the optical extinction coefficient of a ferrofluid with magnetically induced particle agglomeration. The model predicts the existence of a polarization independent component of the optical extinction coefficient that is experimentally measurable at 54.74 o polarization angle. The change in the optical extinction of light polarized at 54.74 o is positive if only the formation of straight n-particle chains is considered and may become negative in the hypothesis that the longer chains degenerate to more isotropic structures (polymer-like coils, globules or bundles of chains). The model for the influence on the light absorption of the long-range pair correlations, published elsewhere, predicts that the change in the optical extinction of light polarized at 54.74 o is always negative, the more

  7. Polarization sensitivity of light diffraction for periodic array of anisotropic gold nanoparticles

    International Nuclear Information System (INIS)

    Tsai, Ming-shan; Liu, Tung-kai; Tsen, Chun-yu; Ting, Chen-ching

    2015-01-01

    This article aims to analyze the first order diffraction intensity of the incident polarized light which is diffracted by the gold nanoparticles array in terms of the surface plasmon effect. The inspected gold nanoparticles array films are built in grating pattern with stripe thickness of 4 μm and diameters of gold nanoparticles ca. 10–56 nm, which are formed by annealing at temperatures of 400, 450, 500, and 550 °C, respectively. The probing light is linearly polarized with wavelengths of 450–800 nm and counterclockwise turns its polarization direction from 0° to 90° during measurements. The results show that the diffraction intensity depends on the anisotropic configuration samples which gold nanoparticles are orientated by analyzing the scanning electron microscope images. It results that the localized surface plasmon effect induced by incident field depends on orientation and causes the sample polarization-sensitive

  8. Optical asymmetric cryptography based on elliptical polarized light linear truncation and a numerical reconstruction technique.

    Science.gov (United States)

    Lin, Chao; Shen, Xueju; Wang, Zhisong; Zhao, Cheng

    2014-06-20

    We demonstrate a novel optical asymmetric cryptosystem based on the principle of elliptical polarized light linear truncation and a numerical reconstruction technique. The device of an array of linear polarizers is introduced to achieve linear truncation on the spatially resolved elliptical polarization distribution during image encryption. This encoding process can be characterized as confusion-based optical cryptography that involves no Fourier lens and diffusion operation. Based on the Jones matrix formalism, the intensity transmittance for this truncation is deduced to perform elliptical polarized light reconstruction based on two intensity measurements. Use of a quick response code makes the proposed cryptosystem practical, with versatile key sensitivity and fault tolerance. Both simulation and preliminary experimental results that support theoretical analysis are presented. An analysis of the resistance of the proposed method on a known public key attack is also provided.

  9. Polarization-sensitive optical frequency domain imaging based on unpolarized light.

    Science.gov (United States)

    Kim, Ki Hean; Park, B Hyle; Tu, Yupeng; Hasan, Tayyaba; Lee, Byunghak; Li, Jianan; de Boer, Johannes F

    2011-01-17

    Polarization-sensitive optical coherence tomography (PS-OCT) is an augmented form of OCT, providing 3D images of both tissue structure and polarization properties. We developed a new method of polarization-sensitive optical frequency domain imaging (PS-OFDI), which is based on a wavelength-swept source. In this method the sample was illuminated with unpolarized light, which was composed of two orthogonal polarization states (i.e., separated by 180° in the Poincaré sphere) that are uncorrelated to each other. Reflection of these polarization states from within the sample was detected simultaneously and independently using a frequency multiplexing scheme. This simultaneous sample probing with two polarization states enabled determination of the depth-resolved Jones matrices of the sample. Polarization properties of the sample were obtained by analyzing the sample Jones matrices through eigenvector decomposition. The new PS-OFDI system ran at 31K wavelength-scans/s with 3072 pixels per wavelength-scan, and was tested by imaging a polarizer and several birefringent tissues such as chicken muscle and human skin. Lastly the new PS-OFDI was applied to imaging two cancer animal models: a mouse model by injecting cancer cells and a hamster cheek pouch model. These animal model studies demonstrated the significant differences in tissue polarization properties between cancer and normal tissues in vivo.

  10. Analysis and Control of Buck-Boost Converter with the Same Input Polarity Based on Novel Energy Factor Evaluation

    Directory of Open Access Journals (Sweden)

    Mahmoud Shaker Nasr

    2017-03-01

    Full Text Available This paper presents firstly a buck-boost circuit with the advantage that its output voltage polarity is the same as the input polarity. The circuit operation is presented and analyzed in different modes of operation. The well known parameters used in evaluation of DC/DC converters like Total Harmonic Distortion THD, Power Factor PF, and Ripple Factor RF have no meaning in DC/DC converters, so it is to introduce efficient concepts to permit a fair evaluation of the converter. This paper present other parameters that can be used to study the characteristics of the converter and gives a real and logic means of its operation. These main parameters are: pumping energy PE, storage energy SE, energy factor EF, and energy losses EL. In addition, the converter efficiency is not considered as 100 % as taken in most analyzing studies. The positive DC/DC buck-boost converter is evaluated according to the new concepts and the system model is deduced for different cases of operation taking into account the resistance of the circuit inductor. The circuit is implemented practically and the presented obtained results show the correct operation under different modes of operation. In addition the control design of the converter is built such that a PI controller with windup is considered. In order to test the effectiveness of the designed control algorithm, the system were exposed to different voltage reference values and the obtained results demonstrate that the system responses for all cases are very acceptable according to the criteria of the control system theory.

  11. Komar fluxes of circularly polarized light beams and cylindrical metrics

    Science.gov (United States)

    Lynden-Bell, D.; Bičák, J.

    2017-11-01

    The mass per unit length of a cylindrical system can be found from its external metric as can its angular momentum. Can the fluxes of energy, momentum, and angular momentum along the cylinder also be so found? We derive the metric of a beam of circularly polarized electromagnetic radiation from the Einstein-Maxwell equations. We show how the uniform plane wave solutions miss the angular momentum carried by the wave. We study the energy, momentum, angular momentum, and their fluxes along the cylinder both for this beam and in general. The three Killing vectors of any stationary cylindrical system give three Komar flux vectors which in turn give six conserved fluxes. We elucidate Komar's mysterious factor 2 by evaluating Komar integrals for systems that have no trace to their stress tensors. The Tolman-Komar formula gives twice the energy for such systems which also have twice the gravity. For other cylindrical systems their formula gives correct results.

  12. Reconfigurable terahertz grating with enhanced transmission of TE polarized light

    Directory of Open Access Journals (Sweden)

    J. W. He

    2017-07-01

    Full Text Available We demonstrate an optically reconfigurable grating with enhanced transmission of TE-polarized waves in the terahertz (THz waveband. This kind of grating is realized by projecting a grating image onto a thin Si wafer with a digital micromirror device (DMD. The enhanced transmission is caused by a resonance of the electromagnetic fields between the photoexcited strips. The position of the transmission peak shifts with the variation of the period and duty cycle of the photoinduced grating, which can be readily controlled by the DMD. Furthermore, a flattened Gaussian model was applied to describe the distribution of the photoexcited free carriers in the Si wafer, and the simulated transmittance spectra are shown to be in good agreement with the experimental results. In future, the photoexcited carriers could also be used to produce THz diffractive elements with reconfigurable functionality.

  13. Polarization resolved conoscopic patterns in nematic cells: effects induced by the incident light ellipticity

    Science.gov (United States)

    Buinyi, Igor O.; Soskin, Marat S.; Vovk, Roman G.

    2008-05-01

    Topological structure of the polarization resolved conoscopic patterns, calculated theoretically and measured experimentally for nematic liquid crystal (NLC) cells, is described in terms of polarization singularities, saddle points and bifurcation lines. The parametric dynamics of the topological network, induced by the variation of the incident light ellipticity, is analyzed for the nematic cells with uniform and non-uniform director configuration. Different stages of similar dynamics are observed for homeotropically oriented NLC cell. Non-uniform director configuration within the cell results in broken central symmentry in the arrangement of the topological network. Main features of the experimentally obtained polarization resolved conoscopic patterns are the same to the theoretically predicted ones.

  14. Injection and detection of a spin-polarized current in a light-emitting diode

    Science.gov (United States)

    Fiederling, R.; Keim, M.; Reuscher, G.; Ossau, W.; Schmidt, G.; Waag, A.; Molenkamp, L. W.

    1999-12-01

    The field of magnetoelectronics has been growing in practical importance in recent years. For example, devices that harness electronic spin-such as giant-magnetoresistive sensors and magnetoresistive memory cells-are now appearing on the market. In contrast, magnetoelectronic devices based on spin-polarized transport in semiconductors are at a much earlier stage of development, largely because of the lack of an efficient means of injecting spin-polarized charge. Much work has focused on the use of ferromagnetic metallic contacts, but it has proved exceedingly difficult to demonstrate polarized spin injection. More recently, two groups have reported successful spin injection from an NiFe contact, but the observed effects of the spin-polarized transport were quite small (resistance changes of less than 1%). Here we describe a different approach, in which the magnetic semiconductor BexMnyZn1-x-ySe is used as a spin aligner. We achieve injection efficiencies of 90% spin-polarized current into a non-magnetic semiconductor device. The device used in this case is a GaAs/AlGaAs light-emitting diode, and spin polarization is confirmed by the circular polarization state of the emitted light.

  15. POLARIZED LIGHT APPLICATION AT CHRONIC INSOMNIA AND HABIT OF SMOKING

    OpenAIRE

    D. Tubič; M. Skorbič

    2016-01-01

    In the treatment of patients with situational neurosis, which for years suffered from insomnia, we used a BIOPTRON-2 device. After 10 everyday evening sessions, the process of falling asleep was normalized, and night sleep was maintained with no additional drugs. A group of 30 patients with a chronic habit of intensive smoking was subjected to applications of BIOPTRON-2 generated PILER light for 10 days. In a considerable part of the tested persons, we noticed a decrease in the inclination fo...

  16. Sensing system with USB camera for experiments of polarization of the light

    Directory of Open Access Journals (Sweden)

    José Luís Fabris

    2017-08-01

    Full Text Available This work shows a sensor system for educational experiments, composed of a USB camera and a software developed and provided by the authors. The sensor system is suitable for the purpose of studying phenomena related to the polarization of the light. The system was tested in experiments performed to verify the Malus’ Law and the spectral efficiency of polarizers. Details of the experimental setup are shown. The camera captures the light in the visible spectral range from a LED that illuminates a white screen after passing through two polarizers. The software uses the image captured by the camera to provide the relative intensity of the light. With the use of two rotating H-sheet linear polarizers, a linear fitting of the Malus’s Law to the transmitted light intensity data resulted in correlation coefficients R larger than 0.9988. The efficiency of the polarizers in different visible spectral regions was verified with the aid of color filters added to the experimental setup. The system was also used to evaluate the intensity time stability of a white LED.

  17. Multiple-input multiple-output visible light communication system based on disorder dispersion components

    Science.gov (United States)

    Yang, Tao; Zhang, Qi; Hao, Yue; Zhou, Xin-hui; Yi, Ming-dong; Wei, Wei; Huang, Wei; Li, Xing-ao

    2017-10-01

    A multiple-input multiple-output visible light communication (VLC) system based on disorder dispersion components is presented. Instead of monochromatic sources and large size photodetectors used in the traditional VLC systems, broadband sources with different spectra act as the transmitters and a compact imaging chip sensor accompanied by a disorder dispersion component and a calculating component serve as the receivers in the proposed system. This system has the merits of small size, more channels, simple structure, easy integration, and low cost. Simultaneously, the broadband sources are suitable to act as illumination sources for their white color. A regularized procedure is designed to solve a matrix equation for decoding the signals at the receivers. A proof-of-concept experiment using on-off keying modulation has been done to prove the feasibility of the design. The experimental results show that the signals decoded by the receivers fit well with those generated from the transmitters, but the bit error ratio is increased with the number of the signal channels. The experimental results can be further improved using a high-speed charge-coupled device, decreasing noises, and increasing the distance between the transmitters and the receivers.

  18. Electric field Monte Carlo simulation of polarized light propagation in multi-layered media

    Science.gov (United States)

    Ding, Chizhu; Tan, Zuojun; Zhang, Shuhui; Chen, Siyu

    2017-10-01

    Electric field Monte Carlo (EMC) simulation is capable of modeling the polarization and coherence phenomena of light. Previous EMC program treat the turbid media as an infinite slab. An electric field Monte Carlo simulation of polarized light propagation in multi-layered media (EMCML) is presented in this paper. The complex electric field vectors are traced during the scattering and the reflection (or refraction) events. In order to improve the computational efficiency, our EMCML program is implemented in parallel in the GPU. The validity of EMCML is demonstrated by comparison between simulation results obtained by EMCML and previously reported programs.

  19. Candidate magnetic dust structures for star light polarization

    Science.gov (United States)

    Papoular, R.

    2017-11-01

    Rotation damping and alignment are discussed as prerequisites for polarization. An expression is derived from first principles, for the damping time of the rotation of a particle in a magnetic field, under the Faraday braking torque, provided its electrical properties are known. This makes it possible to describe mathematically, in great detail, the motion of the particle and determine its ultimate state of motion, if a steady state is possible at all. This work defines, first, the necessary condition for the Faraday braking to be effective: (a) the net electronic charge distribution should not be uniform throughout and (b) the number of vibration modes should exceed a few tens. Resonance of rotation frequency with any of these modes is not a requirement. For alignment to be possible, the ratio of gyroscopic and conservative magnetic to non-conservative (retarding) magnetic torques must be low. Either dia-, para- or ferromagnetism can do, and a small susceptibility is enough and even preferable. This opens up a wide spectrum of possible candidates. A few examples are given.

  20. Polarization independent asymmetric light absorption in plasmonic nanostructure

    Science.gov (United States)

    Franco Rêgo, Davi; Rodriguez-Esquerre, Vitaly Felix

    2017-08-01

    The directional dependency of the optical coefficients, such as absorbance and reflectance, of a periodic hole plasmonic structure is numerically simulated and investigated. The tridimensional structure, which is composed of a metallic thin layer on a semiconductor matrix, is polarization independent and exhibits wide angle tolerance. It is found that the optical coefficients of the simulated structure have strong dependency to the radii of the holes due to cavity modes resonance and surface plasmon resonance. Simulations were carried out using gold and silver, varying the holes radii ranging from 40 to 70nm, as well as its depth, from 30 to 60nm of the metallic thin layer and from 100 to 200nm of the semiconductor matrix. A maximum contrast ratio of a unit was obtained. The resonant modes excited in the structure and excitation of surface plasmon polaritons in the metallic side illumination favors absorption, which explains the asymmetric behavior. We also investigate the structure's fabrication sensitivity by randomizing the generation of center of the holes in a supercell. These findings are significant for a diverse range of applications, ranging from optical integrated circuits to solar and thermovoltaics energy harvesting.

  1. POLARIZED LIGHT APPLICATION AT CHRONIC INSOMNIA AND HABIT OF SMOKING

    Directory of Open Access Journals (Sweden)

    D. Tubič

    2016-06-01

    Full Text Available In the treatment of patients with situational neurosis, which for years suffered from insomnia, we used a BIOPTRON-2 device. After 10 everyday evening sessions, the process of falling asleep was normalized, and night sleep was maintained with no additional drugs. A group of 30 patients with a chronic habit of intensive smoking was subjected to applications of BIOPTRON-2 generated PILER light for 10 days. In a considerable part of the tested persons, we noticed a decrease in the inclination for smoking and an increase in the wish for final putting an end to smoke.

  2. Gamma-Ray Pulsar Light Curves in Offset Polar Cap Geometry

    Science.gov (United States)

    Harding, Alice K.; DeCesar, Megan; Miller, M. Coleman

    2011-01-01

    Recent studies have shown that gamma-ray pulsar light curves are very sensitive to the geometry of the pulsar magnetic field. Pulsar magnetic field geometries, such as the retarded vacuum dipole and force-free magnetospheres, used to model high-energy light curves have distorted polar caps that are offset from the magnetic axis in the direction opposite to rotation. Since this effect is due to the sweepback of field lines near the light cylinder, offset polar caps are a generic property of pulsar magnetospheres and their effects should be included in gamma-ray pulsar light curve modeling. In slot gap models (having two-pole caustic geometry), the offset polar caps cause a strong azimuthal asymmetry of the particle acceleration around the magnetic axis. We have studied the effect of the offset polar caps in both retarded vacuum dipole and force-free geometry on the model high-energy pulse profile. We find that. corn pared to the profile:-; derived from :-;ymmetric caps, the flux in the pulse peaks, which are caustics formed along the trailing magnetic field lines. increases significantly relative to the off-peak emission. formed along leading field lines. The enhanced contrast produces greatly improved slot gap model fits to Fermi pulsar light curves like Vela, which show very little off-peak emIssIon.

  3. Vector Sky Glint Corrections for Above Surface Retrieval of the Subsurface Polarized Light Field

    Science.gov (United States)

    Gilerson, A.; Foster, R.; McGilloway, A.; Ibrahim, A.; El-habashi, A.; Carrizo, C.; Ahmed, S.

    2016-02-01

    Knowledge of the underwater light field is fundamental to determining the health of the world's oceans and coastal regions. For decades, traditional remote sensing retrieval methods that rely solely on the spectral intensity of the water-leaving light have provided indicators of marine ecosystem health. As the demand for retrieval accuracy rises, use of the polarized nature of light as an additional remote sensing tool is becoming necessary. In order to observe the underwater polarized light field from above the surface (for ship, shore, or satellite applications), a method of correcting the above water signal for the effects of polarized surface-reflected skylight is needed. For three weeks in July-August 2014, the NASA Ship Aircraft Bio-Optical Research (SABOR) cruise continuously observed the polarized radiance of the ocean and the sky using a HyperSAS-POL system. The system autonomously tracks the Sun position and the heading of the research vessel in order to maintain a fixed relative solar azimuth angle (i.e. ±90°) and therefore avoid the specular reflection of the sunlight. Additionally, in-situ inherent optical properties (IOPs) were continuously acquired using a set of instrument packages modified for underway measurement, hyperspectral radiometric measurements were taken manually at all stations, and an underwater polarimeter was deployed when conditions permitted. All measurements, above and below the sea surface, were combined and compared in an effort to first develop a glint (sky + Sun) correction scheme for the upwelling polarized signal from a wind-driven ocean surface and compare with one assuming that the ocean surface is flat. Accurate retrieval of the subsurface vector light field is demonstrated through comparisons with polarized radiative transfer codes and direct measurements made by the underwater polarimeter.

  4. Impact of spin-zero particle-photon interactions on light polarization in external magnetic fields

    International Nuclear Information System (INIS)

    Liao Yi

    2007-01-01

    If the recent PVLAS results on polarization changes of a linearly polarized laser beam passing through a magnetic field are interpreted by an axion-like particle, it is almost certain that it is not a standard QCD axion. Considering this, we study the general effective interactions of photons with spin-zero particles without restricting the latter to be a pseudo-scalar or a scalar, i.e., a parity eigenstate. At the lowest order in effective field theory, there are two dimension-5 interactions, each of which has previously been treated separately for a pseudo-scalar or a scalar particle. By following the evolution in an external magnetic field of the system of spin-zero particles and photons, we compute the changes in light polarization and the transition probability for two experimental set-ups: one-way propagation and round-trip propagation. While the first may be relevant for astrophysical sources of spin-zero particles, the second applies to laboratory optical experiments like PVLAS. In the one-way propagation, interesting phenomena can occur for special configurations of polarization where, for instance, transition occurs but light polarization does not change. For the round-trip propagation, however, the standard results of polarization changes for a pseudoscalar or a scalar are only modified by a factor that depends on the relative strength of the two interactions

  5. Nonlinear optical responses to circularly polarized lights of the surface state of a topological insulator

    Science.gov (United States)

    Misawa, Tetsuro; Yokoyama, Takehito; Murakami, Shuichi

    2012-02-01

    Recent photoelectron spectroscopy experiments have revealed the presence of the Dirac cone on the surface of the topological insulator and its spin-splitting due to the spin-orbit interaction. In general, on spin-orbit coupled systems, electric fields induce spin polarizations as linear and nonlinear responses. Here we investigate the inverse Faraday effect on the surface of the topological insulator. The inverse Faraday effect is a non-linear optical effect where a circularly polarized light induces a dc spin polarization. We employ the Keldysh Green's function method to calculate the induced spin polarization and discuss its frequency dependence. In particular, in the low frequency limit, our analytical result gives the spin polarization proportional to the frequency and the square of the lifetime. As for the finite frequency regime, we employ numerical methods to discuss the resonance due to interband transitions. We also discuss the photogalvanic effect, where an illumination of a circular polarized light generates the dc charge current. Lastly, we evaluate those quantities with realistic parameters.[4pt] [1] T. Misawa, T. Yokoyama, S. Murakami, Phys. Rev. B84, 165407 (2011).

  6. System input-output theoretic three-dimensional measurement based on circular-shaped structured light patterns

    Science.gov (United States)

    Lee, Deokwoo; Krim, Hamid

    2017-07-01

    Alternative approaches to three-dimensional (3-D) reconstruction by employing the concepts of "system identification" and "communication systems" based on structured light patterns are proposed. In addition, a sampling criterion of the light source is derived in the case of using multiple projectors because 3-D reconstruction sometimes employs multiple viewpoints (cameras) and multiple structured light sources (or projectors). To reformulate a reconstruction problem, an input-output (I/O) system theoretic is adopted, and camera(s) and light source(s) that are located at different positions are defined as the output and the input, respectively. Akin to the system identification problem, the ratio of an output to an input, the "system function," is defined as a 3-D measurement result. Alternatively, the reconstruction work can employ the concept of the "modulation and demodulation theory," and the reconstruction work can be reinterpreted as an "input estimation problem." This contribution chiefly deals with approximate reconstruction results that are sufficient for practical applications, such as 3-D object detection, clarification, recognition, and classification, rather than a perfect 3-D reconstruction itself. To that end, the development of an efficient and fast 3-D imaging system framework is proposed.

  7. New shapes of light-cone distributions of the transversely polarized ρ-mesons

    International Nuclear Information System (INIS)

    Bakulev, A.P.; Mikhajlov, S.V.

    2000-01-01

    The leading twist light-cone distributions for transversely polarized ρ-, ρ ' - and b 1 mesons are reanalyzed in the framework of QCD sum rules with nonlocal condensates. Using different kinds of sum rules to obtain reliable predictions, we estimate the 2-, 4-, 6- and 8-th moments for transversely polarized ρ- and ρ ' -meson distributions and reestimate tensor couplings f ρ,ρ ' ,b 1 T . It is stressed that the results of standard sum rules also support our estimation of the second moment of the transversely polarized ρ-meson distribution. New models for light-cone distributions are briefly discussed. Our results are compared with those found by Ball and Braun (1996), and the latter is shown to be incomplete

  8. Multiple scattering of polarized light in birefringent slab media: experimental verifications and simulations.

    Science.gov (United States)

    Otsuki, Soichi

    2018-02-01

    The effective scattering Mueller matrices were measured for backward and forward scattering by applying a narrow polarized light on a polyacrylamide slab gel, which was strained vertically to generate birefringence inside. Monte Carlo simulations were performed in conditions that were the same as possible. The measured and simulated matrices were simplified to the reduced ones. They agreed well in both original and reduced forms. While they approximately take reciprocal forms for backward scattering, they approximately satisfy matrix forms that correspond to a reciprocal position of the mirror image for forward scattering. The reduced matrices were factorized by the Lu-Chipman polar decomposition to obtain the polarization parameters. The polarization parameters were in good agreement between the measurement and simulation and showed characteristic features of anisotropic slab media with a birefringence axis parallel to the slab surface.

  9. Polarized light imaging of birefringence and diattenuation at high resolution and high sensitivity

    International Nuclear Information System (INIS)

    Mehta, Shalin B; Shribak, Michael; Oldenbourg, Rudolf

    2013-01-01

    Polarized light microscopy provides unique opportunities for analyzing the molecular order in man-made and natural materials, including biological structures inside living cells, tissues, and whole organisms. 20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging and digital image processing for fast and comprehensive image acquisition and analysis. The LC-PolScope is commonly used for birefringence imaging, analyzing the spatial and temporal variations of the differential phase delay in ordered and transparent materials. Here we describe an alternative use of the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship between the quantities measured with each instrument, and touch on the physical connection between refractive index, birefringence, transmittance, diattenuation, and dichroism. (special issue article)

  10. [Particle Size and Number Density Online Analysis for Particle Suspension with Polarization-Differentiation Elastic Light Scattering Spectroscopy].

    Science.gov (United States)

    Chen, Wei-kang; Fang, Hui

    2016-03-01

    The basic principle of polarization-differentiation elastic light scattering spectroscopy based techniques is that under the linear polarized light incidence, the singlely scattered light from the superficial biological tissue and diffusively scattered light from the deep tissue can be separated according to the difference of polarization characteristics. The novel point of the paper is to apply this method to the detection of particle suspension and, to realize the simultaneous measurement of its particle size and number density in its natural status. We design and build a coaxial cage optical system, and measure the backscatter signal at a specified angle from a polystyrene microsphere suspension. By controlling the polarization direction of incident light with a linear polarizer and adjusting the polarization direction of collected light with another linear polarizer, we obtain the parallel polarized elastic light scattering spectrum and cross polarized elastic light scattering spectrum. The difference between the two is the differential polarized elastic light scattering spectrum which include only the single scattering information of the particles. We thus compare this spectrum to the Mie scattering calculation and extract the particle size. We then also analyze the cross polarized elastic light scattering spectrum by applying the particle size already extracted. The analysis is based on the approximate expressions taking account of light diffusing, from which we are able to obtain the number density of the particle suspension. We compare our experimental outcomes with the manufacturer-provided values and further analyze the influence of the particle diameter standard deviation on the number density extraction, by which we finally verify the experimental method. The potential applications of the method include the on-line particle quality monitoring for particle manufacture as well as the fat and protein density detection of milk products.

  11. Treatment of carpal tunnel syndrome with polarized polychromatic noncoherent light (Bioptron light): a preliminary, prospective, open clinical trial.

    Science.gov (United States)

    Stasinopoulos, D; Stasinopoulos, I; Johnson, M I

    2005-04-01

    Our aim was to assess the efficacy of polarized polychromatic noncoherent light (Bioptron light) in the treatment of idiopathic carpal tunnel syndrome. Carpal tunnel syndrome is the most common compression neuropathy, but no satisfactory conservative treatment is available at present. An uncontrolled experimental study was conducted in patients who visited our clinic from mid-2001 to mid-2002. A total of 25 patients (22 women and three men) with unilateral idiopathic carpal tunnel syndrome, mild to moderate nocturnal pain, and paraesthesia lasting >3 months participated in the study. The average age of the patients was 47.4 years and the average duration of patients' symptoms was 5.2 months. Polarized polychromatic noncoherent light (Bioptron light) was administered perpendicular to the carpal tunnel area. The irradiation time for each session was 6 min at an operating distance of 5-10 cm from the carpal tunnel area, three times weekly for 4 weeks. Outcome measures used were the participants' global assessments of nocturnal pain and paraesthesia, respectively, at 4 weeks and 6 months. At 4 weeks, two patients (8%) had no change in nocturnal pain, six (24%) were in slightly less nocturnal pain, 12 (48%) were much better in regard to nocturnal pain and five (20%) were pain-free. At 6 months, three patients (12%) were slightly better in regard to nocturnal pain, 13 (52%) were much better regarding nocturnal pain, and nine patients (36%) were pain-free. At 4 weeks, four patients (16%) had no change in paraesthesia, five (20%) were slightly better, 13 patients (52%) were much better, and three patients (12%) were without paraesthesia. At 6 months, two patients (8%) had no change in paraesthesia, two (8%) were slightly better, 14 (56%) were much better, and seven (28%) were without paraesthesia. Nocturnal pain and paraesthesia associated with idiopathic carpal tunnel syndrome improved during polarized polychromatic noncoherent light (Bioptron light) treatment. Controlled

  12. arXiv Black hole superradiance and polarization-dependent bending of light

    CERN Document Server

    Plascencia, Alexis D.

    2017-01-01

    An inhomogeneous pseudo-scalar field configuration behaves like an optically active medium. Consequently, if a light ray passes through an axion cloud surrounding a Kerr black hole, it may experience a polarization-dependent bending. We explore the size and relevance of such effect considering both the QCD axion and a generic axion-like particle.

  13. Intensity-dependent change in polarization state of light in normal ...

    Indian Academy of Sciences (India)

    Intensity-dependent change in polarization state of light in normal incidence on an isotropic nonlinear Kerr medium. Hari Prakash Devendra K ... Devendra K Singh2. Department of Physics, University of Allahabad, Allahabad 211 002, India; Department of Physics, Udai Pratap Autonomous College, Varanasi 221 002, India ...

  14. Contribution of spontaneous polarization and its fluctuations to refraction of light in ferroelectrics

    Czech Academy of Sciences Publication Activity Database

    Markovin, P.A.; Trepakov, Vladimír; Tagantsev, A. K.; Dejneka, Alexandr; Andreev, D. A.

    2016-01-01

    Roč. 58, č. 1 (2016), 134-139 ISSN 1063-7834 R&D Projects: GA ČR GA15-13778S Institutional support: RVO:68378271 Keywords : contribution * spontaneous polarization * fluctuations * refraction * light * ferroelectrics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.860, year: 2016

  15. Myth polar light. Why sky bands, herring lightnings, and solar winds fascinate; Mythos Polarlicht. Warum Himmelsbaender, Heringsblitze und Sonnenwinde faszinieren

    Energy Technology Data Exchange (ETDEWEB)

    Hunnekuhl, Michael

    2014-07-01

    The actual state of knowledge of the polar-light research is in this illustrated volume as entertainingly as scientific-foundedly presented. The pecularities of pola lights beyond the polar-light zones as for instance in Germany are thematized and the conditions and periods, in which it there occurs, explained. Michael Hunnekuhl succeeds to mediate the fascination and emotion and simultaneously to explain the phenomena according to the latest state of science generally understandably. Which very old interpretations and descriptions are transmitted, which imaginations had men of polar lights long before the science could them explain? Hunnekuhl takes the reader along with into the world of legends and myths around the polar light. An experience report from the deeply snowed up wideness of Lapland lets everybody closely participate at a polar-light observation and feel the emotion, which it can fan. Above 70 polar-light pictures of high value and further explaining graphics show the continuously changing play of colors, supplement the explanations, and make the fascination comprehensible. Spectacular polar-light films from the international space station ISS, photographs from sun-observation satellites, as well as a polar-light film in real time are bound in the book via QR codes and make the time dimension and the dynamics of this fascinating natural spectacle alively comprehensible.

  16. Analytic parallel-polarized light imaging technique using various light-emitting diodes: a comparison with skin conductance values.

    Science.gov (United States)

    Kim, D H; Choi, J E; Ryu, H J; Seo, S H; Kye, Y C; Ahn, H H

    2015-05-01

    The quantitative difference of the light reflected from a skin surface can be analyzed using parallel-polarized light (PPL) photography when combined with an analytic technique similar to colorimetric photography. To improve the PPL photography technique as an assessment tool for the evaluation of skin condition using light-emitting diodes (LED) of different colors. Parallel-polarized light images were taken using white and green LED illuminators. The acquired images were transformed to CIELAB coordinates. An in-house skin conductance meter was constructed to assess skin hydration level. A dermatologist evaluated the clinical grading of dryness and glossiness. These clinical severities were also compared statistically with the CIELAB values. As with the green illuminator, the correlation analysis of whole sites showed that the L* value positively correlated with age (r = 0.18677, P < 0.05), and that the a* value has negative and positive relationships with age (r = -0.20528, P < 0.05) and glossiness (r = 0.20885, P < 0.05) respectively. The correlations between CIELAB values and multiple characteristics of skin were more significant when green LED was applied than when white light was applied. In addition, coherent relationships between the grade of dryness and skin conductance values showed that visual assessment could be appropriate for the study as with objective measurement. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Induction of transverse polarity by blue light: an all-or-none response.

    Science.gov (United States)

    Nick, P; Schafer, E

    1991-10-01

    Phototropic stimulation induces a spatial memory. This was inferred from experiments with maize (Zea mays L.) coleoptiles involving opposing blue-light pulses, separated by variable time intervals, and rotation on a horizontal clinostat (Nick and Schafer, 1988b, Planta 175, 380-388). In those experiments, individual seedlings either curved towards the first or towards the second pulse, or they remained straight. Bending, if it occurred, seemed to be an all-or-none response. Intermediates, i.e. plants, bending only weakly, were not observed. In the first part of the present study it was attempted to create such intermediates. For this purpose the strength of the first, inducing, and the second, opposing, pulse was varied. The result was complex: (i) Individual seedlings maintained the all-or-none expression of spatial memory. (ii) However, on the level of the whole population, the time intervals at which a given response type dominated depended on the fluence ratio. (iii) Furthermore, the final curvature was determined by the fluence ratio. These results are discussed in terms of a blue-light-induced transverse polarity. This polarity initiates from a labile precursor, which can be reoriented by an opposing stimulation (indicated by the strong bending towards the second pulse). The strong curvatures towards the first pulse over long time intervals reveal that, eventually, the blue-light-induced transverse polarity becomes stabilised and thus immune to the counterpulse. In the second part of the study, the relation between phototropic transduction and transverse polarity was characterised by a phenomenological approach involving the following points: (i) Sensory adaptation for induction of transverse polarity disappears with a time course similar to that for phototropic sensory adaptatation. (ii) The fluence response for induction of transverse polarity is a saturation curve and not bell-shaped like the curve for phototropism (iii) For strong counterpulses and long

  18. Polarization-independent asymmetric light transmission in all-dielectric photonic structures

    Science.gov (United States)

    Zinkiewicz, Lukasz; Nawrot, Michal; Haberko, Jakub; Wasylczyk, Piotr

    2017-11-01

    We design, optimize and fabricate an all-dielectric photonic structure, having a significant, polarization-independent asymmetry in light transmission for opposite incident wave directions. The device, consisting of a dielectric Bragg mirror topped with a regular grid of micrometer-sized pillars, acting as a diffraction grating, is potentially scalable into industrial production. The light propagation simulation results are confirmed by direct measurement of the difference in light transmission, reaching 0.55 near 780 nm, and exceeding 0.2 over a spectral range spanning from 750 to 820 nm.

  19. Lateral refraction and reflection of light polarized lenses principle. Coplanar lens systems

    International Nuclear Information System (INIS)

    Miranda, L.

    2012-01-01

    Studying the behavior of the linearly polarized light to impact a lens and in the lens itself, resulted in the discovery of a physical principle of optics, not mentioned or used so far. This phenomenon is very useful in practice. Perhaps the manifestation of the phenomenon occurs in the plane perpendicular to the road or optical axis, is due the reason that was not seen before, but it has always been there when polarized light passes through a lens. Known and mastered the principle has been manipulated for better research results, using for the first time a planar lens system, which according to the placement of the lens allows for accurate lags between the light beams ar the exits the system. (Author)

  20. The role of input chirp on phase shifters based on slow and fast light effects in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Chen, Yaohui; Öhman, Filip

    2009-01-01

    We experimentally investigate the initial chirp dependence of slow and fast light effects in a semiconductor optical amplifier followed by an optical filter. It is shown that the enhancement of the phase shift due to optical filtering strongly depends on the chirp of the input optical signal. We...... demonstrate ~120º phase delay as well as ~170º phase advance at a microwave frequency of 19 GHz for different optimum values of the input chirp. The experimental results are shown to be in good agreement with numerical results based on a four-wave mixing model. Finally, a simple physical explanation based...

  1. Developments in Polarization and Energy Control of APPLE-II Undulators at Diamond Light Source

    International Nuclear Information System (INIS)

    Longhi, E C; Bencok, P; Dobrynin, A; Rial, E C M; Rose, A; Steadman, P; Thompson, C; Thomson, A; Wang, H

    2013-01-01

    A pair of 2m long APPLE-II type undulators have been built for the I10 BLADE beamline at Diamond Light Source. These 48mm period devices have gap as well as four moveable phase axes which provide the possibility to produce the full range of elliptical polarizations as well as linear polarization tilted through a full 180deg. The mechanical layout chosen has a 'master and slave' arrangement of the phase axes on the top and bottom. This arrangement allows the use of symmetries to provide operational ease for both changing energy using only the master phase while keeping fixed linear horizontal or circular polarization, as well as changing linear polarization angle while keeping fixed energy [1]. The design allows very fast motion of the master phase arrays, without sacrifice of accuracy, allowing the possibility of mechanical polarization switching at 1Hz for dichroism experiments. We present the mechanical design features of these devices, as well as the results of magnetic measurements and shimming from before installation. Finally, we present the results of characterization of these devices by the beamline, including polarimetry, which has been done on the various modes of motion to control energy and polarization. These modes of operation have been available to users since 2011.

  2. Developments in Polarization and Energy Control of APPLE-II Undulators at Diamond Light Source

    Science.gov (United States)

    Longhi, E. C.; Bencok, P.; Dobrynin, A.; Rial, E. C. M.; Rose, A.; Steadman, P.; Thompson, C.; Thomson, A.; Wang, H.

    2013-03-01

    A pair of 2m long APPLE-II type undulators have been built for the I10 BLADE beamline at Diamond Light Source. These 48mm period devices have gap as well as four moveable phase axes which provide the possibility to produce the full range of elliptical polarizations as well as linear polarization tilted through a full 180deg. The mechanical layout chosen has a 'master and slave' arrangement of the phase axes on the top and bottom. This arrangement allows the use of symmetries to provide operational ease for both changing energy using only the master phase while keeping fixed linear horizontal or circular polarization, as well as changing linear polarization angle while keeping fixed energy [1]. The design allows very fast motion of the master phase arrays, without sacrifice of accuracy, allowing the possibility of mechanical polarization switching at 1Hz for dichroism experiments. We present the mechanical design features of these devices, as well as the results of magnetic measurements and shimming from before installation. Finally, we present the results of characterization of these devices by the beamline, including polarimetry, which has been done on the various modes of motion to control energy and polarization. These modes of operation have been available to users since 2011.

  3. Modeling light entangled in polarization and frequency: case study in quantum cryptography

    Science.gov (United States)

    Myers, John M.

    2005-08-01

    With the recognition of a logical gap between experiments and equations of quantum mechanics comes: (1) a chance to clarify such purely mathematical entities as probabilities, density operators, and partial traces-separated out from the choices and judgments necessary to apply them to describing experiments with devices, and (2) an added freedom to invent equations by which to model devices, stemming from the corresponding freedom in interpreting how these equations connect to experiments. Here I apply a few of these clarifications and freedoms to model polarization-entangled light pulses called for in quantum key distribution (QKD). Available light pulses are entangled not only in polarization but also in frequency. Although absent from the simplified models that initiated QKD, the degree of frequency entanglement of polarization-entangled light pulses is shown to affect the amount of key that can be distilled from raw light signals, in one case by a factor of 4/3. Open questions remain, because QKD brings concepts of quantum decision theory, such as measures of distinguishability, mostly worked out in the context of finite-dimensional vector spaces, into contact with infinite-dimensional Hilbert spaces needed to give expression to optical frequency spectra.

  4. Two electric field Monte Carlo models of coherent backscattering of polarized light.

    Science.gov (United States)

    Doronin, Alexander; Radosevich, Andrew J; Backman, Vadim; Meglinski, Igor

    2014-11-01

    Modeling of coherent polarized light propagation in turbid scattering medium by the Monte Carlo method provides an ultimate understanding of coherent effects of multiple scattering, such as enhancement of coherent backscattering and peculiarities of laser speckle formation in dynamic light scattering (DLS) and optical coherence tomography (OCT) diagnostic modalities. In this report, we consider two major ways of modeling the coherent polarized light propagation in scattering tissue-like turbid media. The first approach is based on tracking transformations of the electric field along the ray propagation. The second one is developed in analogy to the iterative procedure of the solution of the Bethe-Salpeter equation. To achieve a higher accuracy in the results and to speed up the modeling, both codes utilize the implementation of parallel computing on NVIDIA Graphics Processing Units (GPUs) with Compute Unified Device Architecture (CUDA). We compare these two approaches through simulations of the enhancement of coherent backscattering of polarized light and evaluate the accuracy of each technique with the results of a known analytical solution. The advantages and disadvantages of each computational approach and their further developments are discussed. Both codes are available online and are ready for immediate use or download.

  5. The Effect of Incident Light Polarization on Vegetation Bidirectional Reflectance Factor

    Science.gov (United States)

    Georgiev, Georgi T.; Thome, Kurt; Ranson, Kurtis J.; King, Michael D.; Butler, James J.

    2010-01-01

    The Laboratory-based Bidirectional Reflectance Factor (BRF) polarization study of vegetation is presented in this paper. The BRF was measured using a short-arc Xenon lamp/monochromator assembly producing an incoherent, tunable light source with a well-defined spectral bandpass at visible and near-infrared wavelengths of interest at 470 nm and 870 nm and coherent light source at 1.656 microns. All vegetation samples were measured using P and S linearly polarized incident light over a range of incident and scatter angles. By comparing these results, we quantitatively examine how the BRF of the samples depends on the polarization of the incident light. The differences are significant, depend strongly on the incident and scatter angles, and can be as high as 120% at 67 deg incident and 470nm. The global nature of Earth's processes requires consistent long-term calibration of all instruments involved in data retrieval. The BRF defines the reflection characteristics of Earth surface. It provides the reflectance of a target in a specific direction as a function of illumination and viewing geometry. The BRF is a function of wavelength and reflects the structural and optical properties of the surface. Various space and airborne radiometric and imaging remote sensing instruments are used in the remote sensing characterization of vegetation canopies and soils, oceans, or especially large pollution sources. The satellite data is validated through comparison with airborne, ground-based and laboratory-based data in an effort to fully understand the vegetation canopy reflectance, The Sun's light is assumed to be unpolarized at the top of the atmosphere; however it becomes polarized to some degree due to atmospheric effects by the time it reaches the vegetation canopy. Although there are numerous atmospheric correction models, laboratory data is needed for model verification and improvement.

  6. Spectral and spatial properties of polarized light reflections from the arms of squid (Loligo pealeii) and cuttlefish (Sepia officinalis L.).

    Science.gov (United States)

    Chiou, Tsyr-Huei; Mäthger, Lydia M; Hanlon, Roger T; Cronin, Thomas W

    2007-10-01

    On every arm of cuttlefish and squid there is a stripe of high-reflectance iridophores that reflects highly polarized light. Since cephalopods possess polarization vision, it has been hypothesized that these polarized stripes could serve an intraspecific communication function. We determined how polarization changes when these boneless arms move. By measuring the spectral and polarizing properties of the reflected light from samples at various angles of tilt and rotation, we found that the actual posture of the arm has little or no effect on partial polarization or the e-vector angle of the reflected light. However, when the illumination angle changed, the partial polarization of the reflected light also changed. The spectral reflections of the signals were also affected by the angle of illumination but not by the orientation of the sample. Electron microscope samples showed that these stripes are composed of several groups of multilayer platelets within the iridophores. The surface normal to each group is oriented at a different angle, which produces essentially constant reflection of polarized light over a range of viewing angles. These results demonstrate that cuttlefish and squid could send out reliable polarization signals to a receiver regardless of arm orientation.

  7. Electrically switchable photonic liquid crystal devices for routing of a polarized light wave

    Science.gov (United States)

    Rushnova, Irina I.; Melnikova, Elena A.; Tolstik, Alexei L.; Muravsky, Alexander A.

    2018-04-01

    The new mode of LC alignment based on photoalignment AtA-2 azo dye where the refractive interface between orthogonal orientations of the LC director exists without voltage and disappeared or changed with critical voltage has been proposed. The technology to fabricate electrically controlled liquid crystal elements for spatial separation and switching of linearly polarized light beams on the basis of the total internal reflection effect has been significantly improved. Its distinctive feature is the application of a composite alignment material comprising two sublayers of Nylon-6 and AtA-2 photoalignment azo dye offering patterned liquid crystal director orientation with high alignment quality value q = 0 . 998. The fabricated electrically controlled spatially structured liquid crystal devices enable implementation of propagation directions separation for orthogonally polarized light beams and their switching with minimal crosstalk.

  8. Vector magnetometry based on electromagnetically induced transparency in linearly polarized light

    International Nuclear Information System (INIS)

    Yudin, V. I.; Taichenachev, A. V.; Dudin, Y. O.; Velichansky, V. L.; Zibrov, A. S.; Zibrov, S. A.

    2010-01-01

    We develop a generalized principle of electromagnetically induced transparency (EIT) vector magnetometry based on high-contrast EIT resonances and the symmetry of atom-light interaction in the linearly polarized bichromatic fields. Operation of such vector magnetometer on the D 1 line of 87 Rb has been demonstrated. The proposed compass-magnetometer has an increased immunity to shifts produced by quadratic Zeeman and ac-Stark effects, as well as by atom-buffer gas and atom-atom collisions. In our proof-of-principle experiment the detected angular sensitivity to magnetic field orientation is 10 -3 deg/Hz 1/2 , which is limited by laser intensity fluctuations, light polarization quality, and magnitude of the magnetic field.

  9. Multiple scattering of polarized light: comparison of Maxwell theory and radiative transfer theory.

    Science.gov (United States)

    Voit, Florian; Hohmann, Ansgar; Schäfer, Jan; Kienle, Alwin

    2012-04-01

    For many research areas in biomedical optics, information about scattering of polarized light in turbid media is of increasing importance. Scattering simulations within this field are mainly performed on the basis of radiative transfer theory. In this study a polarization sensitive Monte Carlo solution of radiative transfer theory is compared to exact Maxwell solutions for all elements of the scattering Müller matrix. Different scatterer volume concentrations are modeled as a multitude of monodisperse nonabsorbing spheres randomly positioned in a cubic simulation volume which is irradiated with monochromatic incident light. For all Müller matrix elements effects due to dependent scattering and multiple scattering are analysed. The results are in overall good agreement between the two methods with deviations related to dependent scattering being prominent for high volume concentrations and high scattering angles.

  10. Self-organized pattern formation upon femtosecond laser ablation by circularly polarized light

    International Nuclear Information System (INIS)

    Varlamova, Olga; Costache, Florenta; Reif, Juergen; Bestehorn, Michael

    2006-01-01

    Surface ripples generation upon femtosecond laser ablation is attributed to self-organized structure formation from instability. We report that linear arrangements are observed not only for linearly polarized light but also for ablation with circularly polarized light. Long ordered chains of spherical nanoparticles, reminding of bead-strings are almost parallel but exhibit typical non-linear dynamics features such as bifurcations. In a first attempt to understand the self-assembly, we rely on models recently developed for the description of similar structures upon ion beam erosion and for the simulation of instabilities in thin liquid films. Our picture describes an unstable surface layer, non-uniformly eroded through Coulomb repulsion between individual positive charges

  11. Harmonic radiation emission from periodic lattices irradiated by short-pulse elliptically polarized laser light.

    Science.gov (United States)

    Ondarza-Rovira, R; Boyd, T J

    2001-10-01

    Radiated emission at high-order harmonic numbers is observed from thin crystalline layers irradiated by short femtosecond elliptically polarized laser light. The applied external radiation field drives the free electrons in the material to large oscillation amplitudes and harmonics are generated by the electronic response to the periodic lattice potential. A model was modified by introducing a more general expression for the lattice force that by sharpening or by smoothing the potential in turn allows the strength of the electronic perturbation to be varied. The electron motion is computed numerically by solving the electromagnetic force equation and by regarding the lattice potential as a perturbative source. For linearly polarized laser light the radiation spectra are characterized by emission lines forming a flat plateau in the region of low harmonic orders with a sharp cutoff for higher numbers. For circular polarization strong emission is found for two harmonic numbers, the first in the low-harmonic region and the second around the cutoff. By solving analytically the electron motion in an elliptically polarized laser field, an exact expression for the electron displacement in all three spatial directions is found. The amplitude of the oscillations sets the analytic form for calculating the peak harmonic numbers emitted from the laser-lattice interaction. The radiation effect studied here, if detected, might hold some potential as a diagnostic and could be used, in principle, as a method for determining the lattice parameter in crystalline structures.

  12. Quantitative light fluorescence (QLF) and polarized white light (PWL) assessments of dental fluorosis in an epidemiological setting.

    Science.gov (United States)

    Pretty, Iain A; McGrady, Michael; Zakian, Christian; Ellwood, Roger P; Taylor, Andrew; Sharif, Mohammed Owaise; Iafolla, Timothy; Martinez-Mier, E Angeles; Srisilapanan, Patcharawan; Korwanich, Narumanas; Goodwin, Michaela; Dye, Bruce A

    2012-05-20

    To determine if a novel dual camera imaging system employing both polarized white light (PWL) and quantitative light induced fluorescence imaging (QLF) is appropriate for measuring enamel fluorosis in an epidemiological setting. The use of remote and objective scoring systems is of importance in fluorosis assessments due to the potential risk of examiner bias using clinical methods. Subjects were recruited from a panel previously characterized for fluorosis and caries to ensure a range of fluorosis presentation. A total of 164 children, aged 11 years (±1.3) participated following consent. Each child was examined using the novel imaging system, a traditional digital SLR camera, and clinically using the Dean's and Thylstrup and Fejerskov (TF) Indices on the upper central and lateral incisors. Polarized white light and SLR images were scored for both Dean's and TF indices by raters and fluorescence images were automatically scored using software. Data from 164 children were available with a good distribution of fluorosis severity. The automated software analysis of QLF images demonstrated significant correlations with the clinical examinations for both Dean's and TF index. Agreement (measured by weighted Kappa's) between examiners scoring clinically, from polarized photographs and from SLR images ranged from 0.56 to 0.92. The study suggests that the use of a digital imaging system to capture images for either automated software analysis, or remote assessment by raters is suitable for epidemiological work. The use of recorded images enables study archiving, assessment by multiple examiners, remote assessment and objectivity due to the blinding of subject status.

  13. Quantitative Light Fluorescence (QLF and Polarized White Light (PWL assessments of dental fluorosis in an epidemiological setting

    Directory of Open Access Journals (Sweden)

    Pretty Iain A

    2012-05-01

    Full Text Available Abstract Background To determine if a novel dual camera imaging system employing both polarized white light (PWL and quantitative light induced fluorescence imaging (QLF is appropriate for measuring enamel fluorosis in an epidemiological setting. The use of remote and objective scoring systems is of importance in fluorosis assessments due to the potential risk of examiner bias using clinical methods. Methods Subjects were recruited from a panel previously characterized for fluorosis and caries to ensure a range of fluorosis presentation. A total of 164 children, aged 11 years (±1.3 participated following consent. Each child was examined using the novel imaging system, a traditional digital SLR camera, and clinically using the Dean’s and Thylstrup and Fejerskov (TF Indices on the upper central and lateral incisors. Polarized white light and SLR images were scored for both Dean’s and TF indices by raters and fluorescence images were automatically scored using software. Results Data from 164 children were available with a good distribution of fluorosis severity. The automated software analysis of QLF images demonstrated significant correlations with the clinical examinations for both Dean’s and TF index. Agreement (measured by weighted Kappa’s between examiners scoring clinically, from polarized photographs and from SLR images ranged from 0.56 to 0.92. Conclusions The study suggests that the use of a digital imaging system to capture images for either automated software analysis, or remote assessment by raters is suitable for epidemiological work. The use of recorded images enables study archiving, assessment by multiple examiners, remote assessment and objectivity due to the blinding of subject status.

  14. THE EFFECT OF GRAVITATION ON THE POLARIZATION STATE OF A LIGHT RAY

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Tanay; Sen, A. K. [Department of Physics Assam University, Silchar-788011, Assam (India)

    2016-12-10

    In the present work, detailed calculations have been carried out on the rotation of the polarization vector of an electromagnetic wave due to the presence of a gravitational field of a rotating body. This has been done using the general expression of Maxwell’s equation in curved spacetime. Considering the far-field approximation (i.e., the impact parameter is greater than the Schwarzschild radius and rotation parameter), the amount of rotation of the polarization vector as a function of impact parameter has been obtained for a rotating body (considering Kerr geometry). The present work shows that the rotation of the polarization vector cannot be observed in the case of Schwarzschild geometry. This work also calculates the rotational effect when considering prograde and retrograde orbits for the light ray. Although the present work demonstrates the effect of rotation of the polarization vector, it confirms that there would be no net polarization of an electromagnetic wave due to the curved spacetime geometry in a Kerr field.

  15. Influence of InAlN Nanospiral Structures on the Behavior of Reflected Light Polarization

    Directory of Open Access Journals (Sweden)

    Yu-Hung Kuo

    2018-03-01

    Full Text Available The influence of structural configurations of indium aluminum nitride (InAlN nanospirals, grown by reactive magnetron sputter epitaxy, on the transformation of light polarization are investigated in terms of varying structural chirality, growth temperatures, titanium nitride (TiN seed (buffer layer thickness, nanospiral thickness, and pitch. The handedness of reflected circularly polarized light in the ultraviolet–visible region corresponding to the chirality of nanospirals is demonstrated. A high degree of circular polarization (Pc value of 0.75 is obtained from a sample consisting of 1.2 μm InAlN nanospirals grown at 650 °C. A film-like structure is formed at temperatures lower than 450 °C. At growth temperatures higher than 750 °C, less than 0.1 In-content is incorporated into the InAlN nanospirals. Both cases reveal very low Pc. A red shift of wavelength at Pc peak is found with increasing nanospiral pitch in the range of 200–300 nm. The Pc decreases to 0.37 for two-turn nanospirals with total length of 0.7 μm, attributed to insufficient constructive interference. A branch-like structure appears on the surface when the nanospirals are grown longer than 1.2 μm, which yields a low Pc around 0.5, caused by the excessive scattering of incident light.

  16. [Suppression of visceral pain by action of the low intensity polarized light on acupuncture antinociceptive points].

    Science.gov (United States)

    Lymans'kyĭ, Iu P; Tamarova, Z A; Huliar, S O

    2003-01-01

    In experiments on mice, statistically authentic weakening of visceral pain has been shown after an action of low intensity polarized light from a device Bioptron on antinociceptive acupuncture points (AP). Pain was caused by an intraperitoneal injection of 2% acetic acid (0.1 ml/10 g). The intensity of pain was judged on duration and frequency of painful behavioral reactions (writhing, licking of abdomen), as well as on duration of sleep, eating and motor activity. In animals which immediately after injections of acetic acid were exposed to polarized light of low intensity for 10 min, applied on any of antinociceptive APs (E-36, E-43, VC-8, RP-6), the duration of painful behavioral reaction was determined to be reduced, while that of non-painful one increased. The comparison of the total duration of the writhing at control and experimental mice showed that an activation of AP E-43 induced the greatest analgesic effect (76.5%), from AP VC-8 it was 76.3%, from RP-6--46.8%, and from E-36--41.4%. We have concluded that the effect of polarized light of low intensity on APs was a convenient non-pharmacological method of treating visceral pain.

  17. Electric field Monte Carlo simulation of polarized light propagation in turbid media.

    Science.gov (United States)

    Xu, Min

    2004-12-27

    A Monte Carlo method based on tracing the multiply scattered electric field is presented to simulate the propagation of polarized light in turbid media. Multiple scattering of light comprises a series of updates of the parallel and perpendicular components of the complex electric field with respect to the scattering plane by the amplitude scattering matrix and rotations of the local coordinate system spanned by the unit vectors in the directions of the parallel and perpendicular electric field components and the propagation direction of light. The backscattering speckle pattern and the backscattering Mueller matrix of an aqueous suspension of polystyrene spheres in a slab geometry are computed using this Electric Field Monte Carlo (EMC) method. An efficient algorithm computing the Mueller matrix in the pure backscattering direction is detailed in the paper.

  18. Anisotropy-Guided Enantiomeric Enhancement in Alanine Using Far-UV Circularly Polarized Light.

    Science.gov (United States)

    Meinert, Cornelia; Cassam-Chenaï, Patrick; Jones, Nykola C; Nahon, Laurent; Hoffmann, Søren V; Meierhenrich, Uwe J

    2015-06-01

    All life on Earth is characterized by its asymmetry - both the genetic material and proteins are composed of homochiral monomers. Understanding how this molecular asymmetry initially arose is a key question related to the origins of life. Cometary ice simulations, L-enantiomeric enriched amino acids in meteorites and the detection of circularly polarized electromagnetic radiation in star-forming regions point to a possible interstellar/protostellar generation of stereochemical asymmetry. Based upon our recently recorded anisotropy spectra g(λ) of amino acids in the vacuum-UV range, we subjected amorphous films of racemic (13)C-alanine to far-UV circularly polarized synchrotron radiation to probe the asymmetric photon-molecule interaction under interstellar conditions. Optical purities of up to 4% were reached, which correlate with our theoretical predictions. Importantly, we show that chiral symmetry breaking using circularly polarized light is dependent on both the helicity and the wavelength of incident light. In order to predict such stereocontrol, time-dependent density functional theory was used to calculate anisotropy spectra. The calculated anisotropy spectra show good agreement with the experimental ones. The European Space Agency's Rosetta mission, which successfully landed Philae on comet 67P/Churyumov-Gerasimenko on 12 November 2014, will investigate the configuration of chiral compounds and thereby obtain data that are to be interpreted in the context of the results presented here.

  19. Simultaneously improving optical absorption of both transverse-electric polarized and transverse-magnetic polarized light for organic solar cells with Ag grating used as transparent electrode

    Directory of Open Access Journals (Sweden)

    Yongbing Long

    2014-08-01

    Full Text Available Theoretical simulations are performed to investigate optical performance of organic solar cells with Ag grating electrode. It is demonstrated that optical absorption for both transverse-electric (TE polarized and transverse-magnetic(TM polarized light is simultaneously improved when compared with that for the device without the Ag grating. The improvement is respectively attributed to the resonance and the surface plasmon polaritons within the device. After an additional WO3 layer is capped on the Ag grating, absorption of TE-polarized light is further improved due to resonance of double microcavities within the device, and absorption of TM-polarized light is improved by the combined effects of the microcavity resonance and the surface plasmon polaritons. Correspondingly, the short current density for randomly polarized light is improved by 18.1% from that of the device without the Ag grating. Finally, it is demonstrated that high transmission may not be an essential prerequisite for metallic gratings when they are used as transparent electrode since absorption loss caused by low transmission can be compensated by using a capping layer to optimize optical resonance of the WMC structure within the device.

  20. Coupling between surface plasmon polaritons and transverse electric polarized light via L-shaped nano-apertures.

    Science.gov (United States)

    Yang, Jing; Hu, Chuang; Wen, Qiuling; Zhao, Chenglong; Zhang, Jiasen

    2015-03-15

    Given that plasmonic fields are intrinsically transverse magnetic (TM), coupling surface plasmon polaritons (SPPs) and transverse electric (TE) polarized light, especially at nanoscale, remain challenging. We propose the use of L-shaped nano-apertures to overcome this fundamental limitation and enable coupling between SPPs and TE polarized light. Polarization conversion originates from the interference of two resonant modes excited in the nano-apertures and the nearly 180° phase retardation between them. The experiments show that both TE-to-plasmon and plasmon-to-TE couplings can be implemented at the subwavelength scale. This discovery provides great freedom when manipulating light based on SPPs at the nanoscale and helps in using the energy of TE polarized light.

  1. BRIEF COMMUNICATIONS: Investigation of the state of polarization of light in a single-mode fiber waveguide

    Science.gov (United States)

    Kozel, S. M.; Kreopalov, V. I.; Listvin, V. N.; Glavatskikh, N. A.

    1983-01-01

    An analysis is made of the polarization anisotropy of a single-mode fiber with a twisted elliptic core. The Jones matrix is obtained and the complex function of the state of polarization of light in a fiber is investigated. The results are reported of measurements of the linear and circular birefringence of a borosilicate single-mode glass fiber.

  2. Generalized processor sharing with light-tailed and heavy-tailed input

    NARCIS (Netherlands)

    Borst, Sem; Mandjes, M.R.H.; van Uitert, Miranda

    2003-01-01

    We consider a queue fed by a mixture of light-tailed and heavy-tailed traffic. The two traffic flows are served in accordance with the generalized processor sharing (GPS) discipline. GPS-based scheduling algorithms, such as weighted fair queueing, have emerged as an important mechanism for achieving

  3. Electric field Monte Carlo simulation of coherent backscattering of polarized light by a turbid medium containing Mie scatterers.

    Science.gov (United States)

    Sawicki, John; Kastor, Nikolas; Xu, Min

    2008-04-14

    A method for directly simulating coherent backscattering of polarized light by a turbid medium has been developed based on the Electric field Monte Carlo (EMC) method. Electric fields of light traveling in a pair of time-reversed paths are added coherently to simulate their interference. An efficient approach for computing the electric field of light traveling along a time-reversed path is derived and implemented based on the time-reversal symmetry of electromagnetic waves. Coherent backscattering of linearly and circularly polarized light by a turbid medium containing Mie scatterers is then investigated using this method.

  4. Light trapping and circularly polarization at a Dirac point in 2D plasma photonic crystals

    Science.gov (United States)

    Li, Qian; Hu, Lei; Mao, Qiuping; Jiang, Haiming; Hu, Zhijia; Xie, Kang; Wei, Zhang

    2018-03-01

    Light trapping at the Dirac point in 2D plasma photonic crystal has been obtained. The new localized mode, Dirac mode, is attributable to neither photonic bandgap nor total internal reflection. It exhibits a unique algebraic profile and possesses a high-Q factor resonator of about 105. The Dirac point could be modulated by tuning the filling factor, plasma frequency and plasma cyclotron frequency, respectively. When a magnetic field parallel to the wave vector is applied, Dirac modes for right circularly polarized and left circularly polarized waves could be obtained at different frequencies, and the Q factor could be tuned. This property will add more controllability and flexibility to the design and modulation of novel photonic devices. It is also valuable for the possibilities of Dirac modes in photonic crystal containing other kinds of metamaterials.

  5. Kaleidoscope of oral artifacts: A vivid picture through light and polarizing microscope.

    Science.gov (United States)

    Kardam, Priyanka; Jain, Kanu; Mehendiratta, Monica; Mathias, Yulia

    2016-01-01

    This study is based on finding of an inexplicable artifact that was seen in the tissue received as periapical granuloma. To observe the histological appearance of different commonly implanted food particles and easily incorporated substances from a laboratory in the oral biopsy tissues. Various food particles such as wheat chapatti, beans, peas, pulses, and coriander leaves and substances such as a suture, cotton, and paper that can easily gain entry during biopsy and histotechnical procedures were intentionally introduced in the tissue specimens of a uterus from outside. Both light and polarizing microscopes were utilized to view them. Different food particles and substances gave different appearances that could lead to misdiagnosis. Some of these also exhibited positive birefringence under the polarizing microscope. Knowledge and familiarity with probable foreign substances which can appear in tissues may help prevent misdiagnosis or erroneous diagnosis of biopsy specimens.

  6. Light Microscopy and Polarized Microscopy: A Dermatological Tool to Diagnose Gray Hair Syndromes.

    Science.gov (United States)

    Chandravathi, P L; Karani, Hetal Deepak; Siddaiahgari, Sirisha Rani; Lingappa, Lokesh

    2017-01-01

    Gray hair syndromes are rare syndromes which have an autosomal recessive inheritance and are characterized by pigmentary dilution of skin and hair, defects in immunological function, and nervous system defects. They comprise three disorders namely Chediak-Higashi syndrome (CHS), Griscelli syndrome (GPS), and Elejalde syndrome. Clinically, it is difficult to distinguish these disorders as their clinical features may overlap. Hence, to make a correct diagnosis and differentiate between CHS and GPS light microscopic examination of skin and hair shafts as well as peripheral blood smear evaluations should be done. In cases where the diagnosis is not possible chromosomal analysis for specific mutations can be done. In resource-poor settings where chromosomal analysis is not possible, and light microscopy findings are inconclusive, polarized microscopy can serve as a useful tool to distinguish between CHS and GPS. We report three cases with gray hair syndromes where the diagnosis on light microscopy and polarized microscopy of hair shaft correlated with the bone marrow examination findings and chromosomal analysis, thus emphasizing the importance of a noninvasive, cost-effective, and time-saving alternative in the diagnosis of these syndromes.

  7. Intracellular photoreceptive site for blue light-induced cell division in protonemata of the fern Adiantum [Pteridophyta]: Further analyses by polarized light irradiation and cell centrifugation

    International Nuclear Information System (INIS)

    Kadota, A.; Fushimi, Y.; Wada, M.

    1986-01-01

    The intracellular localization of the photoreceptive site for blue light-induced cell division in single-celled protonemata of Adiantum capillus-veneris L. was investigated using polarized light irradiation and protonemal cell centrifugation. The response to irradiation with polarized blue light showed no dependence on the direction of light polarization. However, centrifugation of the protonemata followed by microbeam irradiation showed that the site of blue light perception could be displaced together with the nucleus. Centrifugal treatment changed the distribution of intracellular organelles at the time of light exposure and basipetally displaced the nucleus about 90μm. This treatment had no effect on the induction of cell division with blue light if the protonemata were centrifuged again acropetally after the light treatment. Microbeam (30×30 μm2) irradiation with blue light of the apical 45–75 βm region, the receptive site of blue light in non-centrifuged cell, did not induce cell division. However, cell division was induced by irradiation of the nucleus-containing region, indicating that the photoreceptive site was displaced together with the nucleus by the centrifugation. These results suggest that the blue light receptor regulating cell division in Adiantum protonemata is not likely to be located on the plasma membrane. (author)

  8. Evaluating fibre orientation dispersion in white matter: Comparison of diffusion MRI, histology and polarized light imaging.

    Science.gov (United States)

    Mollink, Jeroen; Kleinnijenhuis, Michiel; Cappellen van Walsum, Anne-Marie van; Sotiropoulos, Stamatios N; Cottaar, Michiel; Mirfin, Christopher; Heinrich, Mattias P; Jenkinson, Mark; Pallebage-Gamarallage, Menuka; Ansorge, Olaf; Jbabdi, Saad; Miller, Karla L

    2017-08-15

    Diffusion MRI is an exquisitely sensitive probe of tissue microstructure, and is currently the only non-invasive measure of the brain's fibre architecture. As this technique becomes more sophisticated and microstructurally informative, there is increasing value in comparing diffusion MRI with microscopic imaging in the same tissue samples. This study compared estimates of fibre orientation dispersion in white matter derived from diffusion MRI to reference measures of dispersion obtained from polarized light imaging and histology. Three post-mortem brain specimens were scanned with diffusion MRI and analyzed with a two-compartment dispersion model. The specimens were then sectioned for microscopy, including polarized light imaging estimates of fibre orientation and histological quantitative estimates of myelin and astrocytes. Dispersion estimates were correlated on region - and voxel-wise levels in the corpus callosum, the centrum semiovale and the corticospinal tract. The region-wise analysis yielded correlation coefficients of r = 0.79 for the diffusion MRI and histology comparison, while r = 0.60 was reported for the comparison with polarized light imaging. In the corpus callosum, we observed a pattern of higher dispersion at the midline compared to its lateral aspects. This pattern was present in all modalities and the dispersion profiles from microscopy and diffusion MRI were highly correlated. The astrocytes appeared to have minor contribution to dispersion observed with diffusion MRI. These results demonstrate that fibre orientation dispersion estimates from diffusion MRI represents the tissue architecture well. Dispersion models might be improved by more faithfully incorporating an informed mapping based on microscopy data. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Miniature magnetic bottle confined by circularly polarized laser light and measurements of the inverse Faraday effect in plasmas

    International Nuclear Information System (INIS)

    Eliezer, S.; Paiss, Y.; Horovitz, Y.; Henis, Z.

    1997-01-01

    A new concept of hot plasma confinement in a miniature magnetic bottle induced by circularly polarized laser light is suggested. Magnetic fields generated by circularly polarized laser light may be of the order of megagauss, depending on the laser intensity. In this configuration the circularly polarized light is used to obtain confinement of a plasma contained in a good conductor vessel. The confinement in this scheme is supported by the magnetic forces. The Lawson criterion for a DT plasma might be achieved for number density n = 5*10 21 cm -3 and confinement time τ= 20 ns. The laser and plasma parameters required to obtain an energetic gain are calculated. Experiments and preliminary calculations were performed to study the feasibility of the above scheme. Measurements of the axial magnetic field induced by circularly polarized laser light, the so called inverse Faraday effect, and of the absorption of circularly polarized laser light in plasma, are reported. The experiments were performed with a circularly polarized Nd:YAG laser, having a wavelength of 1.06 τm and a pulse duration of 7 ns, in a range of irradiances from 10 9 to 10 14 W/cm 2 . Axial magnetic fields from 500 Gauss to 2 megagauss were measured. Up to 5*10 13 W/cm 3 the results are in agreement with a nonlinear model of the inverse Faraday effect dominated by the ponderomotive force. For the laser irradiance studied here, 9*10 13 - 2.5*10 14 W/cm 2 , the absorption of circularly polarized light was 14% higher relative to the absorption of linear polarized light

  10. Photoreceptor processing speed and input resistance changes during light adaptation correlate with spectral class in the bumblebee, Bombus impatiens.

    Directory of Open Access Journals (Sweden)

    Peter Skorupski

    Full Text Available Colour vision depends on comparison of signals from photoreceptors with different spectral sensitivities. However, response properties of photoreceptor cells may differ in ways other than spectral tuning. In insects, for example, broadband photoreceptors, with a major sensitivity peak in the green region of the spectrum (>500 nm, drive fast visual processes, which are largely blind to chromatic signals from more narrowly-tuned photoreceptors with peak sensitivities in the blue and UV regions of the spectrum. In addition, electrophysiological properties of the photoreceptor membrane may result in differences in response dynamics of photoreceptors of similar spectral class between species, and different spectral classes within a species. We used intracellular electrophysiological techniques to investigate response dynamics of the three spectral classes of photoreceptor underlying trichromatic colour vision in the bumblebee, Bombus impatiens, and we compare these with previously published data from a related species, Bombus terrestris. In both species, we found significantly faster responses in green, compared with blue- or UV-sensitive photoreceptors, although all 3 photoreceptor types are slower in B. impatiens than in B. terrestris. Integration times for light-adapted B. impatiens photoreceptors (estimated from impulse response half-width were 11.3 ± 1.6 ms for green photoreceptors compared with 18.6 ± 4.4 ms and 15.6 ± 4.4 for blue and UV, respectively. We also measured photoreceptor input resistance in dark- and light-adapted conditions. All photoreceptors showed a decrease in input resistance during light adaptation, but this decrease was considerably larger (declining to about 22% of the dark value in green photoreceptors, compared to blue and UV (41% and 49%, respectively. Our results suggest that the conductances associated with light adaptation are largest in green photoreceptors, contributing to their greater temporal processing speed

  11. Analytical Solutions of Temporal Evolution of Populations in Optically-Pumped Atoms with Circularly Polarized Light

    Directory of Open Access Journals (Sweden)

    Heung-Ryoul Noh

    2016-03-01

    Full Text Available We present an analytical calculation of temporal evolution of populations for optically pumped atoms under the influence of weak, circularly polarized light. The differential equations for the populations of magnetic sublevels in the excited state, derived from rate equations, are expressed in the form of inhomogeneous second-order differential equations with constant coefficients. We present a general method of analytically solving these differential equations, and obtain explicit analytical forms of the populations of the ground state at the lowest order in the saturation parameter. The obtained populations can be used to calculate lineshapes in various laser spectroscopies, considering transit time relaxation.

  12. In-service light path PMD (polarization mode dispersion) monitoring by PMD compensation.

    Science.gov (United States)

    Yao, X Steve; Chen, Xiaojun; Xia, T J; Wellbrock, Glenn; Chen, David; Peterson, Daniel; Zhang, Paul; Belisle, Ansel; Dong, Lei; Yu, Tao

    2010-12-20

    We describe a novel method of measuring PMD (polarization mode dispersion) of an in-service DWDM system by PMD compensation. We successfully demonstrate the method in a 1500-km ultra-long haul DWDM test bed. We further verify the feasibility of the method for in-service light path PMD monitoring in a field trial in a revenue-generating route in Verizon Network, and obtain an accurate PMD value without impacting live network traffic. The discrepancy between the measured and expected PMD values is less than 6% for all cases tested.

  13. Influence of refraction of p-polarized light on photoemission from metallic surface states

    International Nuclear Information System (INIS)

    Bagchi, A.; Barrera, R.G.

    1979-01-01

    The refraction of p-polarized light at a metal surface leads, under certain circumstances, to a large peak in the spatial distribution of the normal component of the electric field near the surface. The origin of this peak is explained both in terms of a classical correspondence and in terms of a theory based on the non-local dielectric response of the metal surface. The significance of the large magnitude and rapid variation of the surface electric field in exciting photoelectrons from surface states is discussed [pt

  14. Light-free magnetic resonance force microscopy for studies of electron spin polarized systems

    International Nuclear Information System (INIS)

    Pelekhov, Denis V.; Selcu, Camelia; Banerjee, Palash; Chung Fong, Kin; Chris Hammel, P.; Bhaskaran, Harish; Schwab, Keith

    2005-01-01

    Magnetic resonance force microscopy is a scanned probe technique capable of three-dimensional magnetic resonance imaging. Its excellent sensitivity opens the possibility for magnetic resonance studies of spin accumulation resulting from the injection of spin polarized currents into a para-magnetic collector. The method is based on mechanical detection of magnetic resonance which requires low noise detection of cantilever displacement; so far, this has been accomplished using optical interferometry. This is undesirable for experiments on doped silicon, where the presence of light is known to enhance spin relaxation rates. We report a non-optical displacement detection scheme based on sensitive microwave capacitive readout

  15. MECHANISMS OF PRIMARY RECEPTION OF ELECTROMAGNETIC WAVES OF OPTICAL RANGE AS A BIOPHYSICAL BASIS OF POLARIZED LIGHT THERAPY

    Directory of Open Access Journals (Sweden)

    S. O. Hulyar

    2015-09-01

    Full Text Available An existence of separate functional system of electromagnetic balance regulation has been substantiated and a working conception of light puncture has been formulated. As a basis, there is a possibility to use the acupuncture points for input of biologically necessary electromagnetic waves into the system of their conductors in a body that might be considered as a transport facility for energy ofthe polarized electromagnetic waves. Zones-recipients are organs having an electromagnetic disbalance due to excess of biologically inadequate radiation and being the targets for peroxide oxidation, foremost, a body has the neurohormonal and immune regulatory systems. Electromagnetic stimulation or modification of functions of the zones-recipients determines achievement of therapeutic and useful effects, and their combination with local reparative processes allows attaining a clinical goal. We represent own and literary experimental data about development of physiological responses (analgesia, bronchospasm control, immune stimulation and inhibition of peroxide oxidation of lipids to BIOPTRON-light exposure on the acupuncture points or biologically active zones. We show the experimental facts in support of a hypothesis that a living organism can perceive an action of the electromagnetic waves of optical range not only via the visual system, but also through the off-nerve receptors (specific energy-sensitive proteins detecting critical changes of energy in cells and functioning as the "sensory" cell systems, as well as via the acupuncture points. This confirms an important role of the electromagnetic waves of optical range in providing normal vital functions of living organisms. A current approach to BIOPTRON light therapy consists in combined (local and system exposure of the electromagnetic waves within the biologically necessary range.

  16. [Scanning electron microscopy and light microscopy under polarized light of a submandibular salivary gland calculus].

    Science.gov (United States)

    Traini, T; Murmura, G; Giammaria, G; Ciavarelli, L; Caputi, S

    2001-05-01

    The salivary calculus is an ancient pathologic condition, called sublingual stone by Hyppocrates. It is well-defined from a anatomo-pathologic, diagnostic and topographic viewpoint, though some pathogenesis-related doubts still exist. This work aims at relating the micro-morpho-structural aspect of a salivary calculus of remarkable dimensions with the current calculogenetic hypotheses. A 1.1 g salivary calculus removed from the initial section of Wrthon s duct in the right-hand submandibular gland of a 42 year old male has been studied. Following the fixation in 4% buffered formalin and the inclusion in resin, it was serially sectioned in 15-20 micron slices. Some sections were coloured with toluidine blue O and acid fuchsin. The exeresis of the calculus was carried out intraorally, with marsupialization under local anesthesia. The analysis was performed using a SEM with backscattered electrons and a polarised and transmitted light microscope. The investigations have outlined the presence of various organic cores and a concentric, stratiform architecture interrupted by radial elements. The formation of this calculus may be due to mixed secondary lithiasis resulting from the formation of colloids and crystalloids.

  17. Polarization ratio enhancement of a-plane GaN light emitting diodes by asymmetric two-dimensional photonic crystals

    International Nuclear Information System (INIS)

    Chou, Yen; Li, Hsiang-Wei; Yin, Yu-Feng; Wang, Yu-Ting; Lin, Yen-Chen; Wu, Yuh-Renn; Huang, Jian Jang; Lin, Da-Wei; Kuo, Hao-Chung

    2014-01-01

    Fabricating photonic crystals (PhCs) on GaN based non-polar light emitting diodes (LEDs) is an effective way to increase light extraction and meanwhile to preserve or improve polarization ratio. In this work, a-plane GaN LEDs with two-dimensional PhCs were demonstrated. With the E // m polarized modes (which mean the optical polarization with the electric field parallel to m-axis) as the target of diffraction, we matched E//m modes to the photonic bands and aligned E//c modes to fall within the photonic band gap. The results show stronger E//m but weaker E//c mode diffractions on both c- and m-axes. At the vertical direction, the polarization ratio is enhanced from 45.8% for the planar device to 52.3% for the LEDs with PhCs

  18. A Spin-Light Polarimeter for Multi-GeV Longitudinally Polarized Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Mohanmurthy, Prajwal [Mississippi State University, Starkville, MS (United States); Dutta, Dipangkar [Mississippi State University, Starkville, MS (United States) and Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01

    The physics program at the upgraded Jefferson Lab (JLab) and the physics program envisioned for the proposed electron-ion collider (EIC) include large efforts to search for interactions beyond the Standard Model (SM) using parity violation in electroweak interactions. These experiments require precision electron polarimetry with an uncertainty of < 0.5 %. The spin dependent Synchrotron radiation, called "spin-light," can be used to monitor the electron beam polarization. In this article we develop a conceptual design for a "spin-light" polarimeter that can be used at a high intensity, multi-GeV electron accelerator. We have also built a Geant4 based simulation for a prototype device and report some of the results from these simulations.

  19. Transfer of polarized light in planetary atmospheres basic concepts and practical methods

    CERN Document Server

    Hovenier, Joop W; Domke, Helmut

    2004-01-01

    The principal elements of the theory of polarized light transfer in planetary atmospheres are expounded in a systematic but concise way. Basic concepts and practical methods are emphasized, both for single and multiple scattering of electromagnetic radiation by molecules and particles in the atmospheres of planets in the Solar System, including the Earth, and beyond. A large part of the book is also useful for studies of light scattering by particles in comets, the interplanetary and interstellar medium, circumstellar disks, reflection nebulae, water bodies like oceans and suspensions of particles in a gas or liquid in the laboratory. Throughout the book symmetry principles, such as the reciprocity principle and the mirror symmetry principle, are employed. In this way the theory is made more transparent and easier to understand than in most papers on the subject. In addition, significant computational reductions, resulting from symmetry principles, are presented. Hundreds of references to relevant literature ...

  20. Lamp-lit bridges as dual light-traps for the night-swarming mayfly, Ephoron virgo: interaction of polarized and unpolarized light pollution.

    Science.gov (United States)

    Szaz, Denes; Horvath, Gabor; Barta, Andras; Robertson, Bruce A; Farkas, Alexandra; Egri, Adam; Tarjanyi, Nikolett; Racz, Gergely; Kriska, Gyorgy

    2015-01-01

    Ecological photopollution created by artificial night lighting can alter animal behavior and lead to population declines and biodiversity loss. Polarized light pollution is a second type of photopollution that triggers water-seeking insects to ovisposit on smooth and dark man-made objects, because they simulate the polarization signatures of natural water bodies. We document a case study of the interaction of these two forms of photopollution by conducting observations and experiments near a lamp-lit bridge over the river Danube that attracts mass swarms of the mayfly Ephoron virgo away from the river to oviposit on the asphalt road of the bridge. Millions of mayflies swarmed near bridge-lights for two weeks. We found these swarms to be composed of 99% adult females performing their upstream compensatory flight and were attracted upward toward unpolarized bridge-lamp light, and away from the horizontally polarized light trail of the river. Imaging polarimetry confirmed that the asphalt surface of the bridge was strongly and horizontally polarized, providing a supernormal ovipositional cue to Ephoron virgo, while other parts of the bridge were poor polarizers of lamplight. Collectively, we confirm that Ephoron virgo is independently attracted to both unpolarized and polarized light sources, that both types of photopollution are being produced at the bridge, and that spatial patterns of swarming and oviposition are consistent with evolved behaviors being triggered maladaptively by these two types of light pollution. We suggest solutions to bridge and lighting design that should prevent or mitigate the impacts of such scenarios in the future. The detrimental impacts of such scenarios may extend beyond Ephoron virgo.

  1. Effect of input spectrum on the spectral switch characteristics in a white-light Michelson interferometer.

    Science.gov (United States)

    Brundavanam, Maruthi M; Viswanathan, Nirmal K; Rao, D Narayana

    2009-12-01

    We report here a detailed experimental study to demonstrate the effect of source spectral characteristics such as spectral bandwidth (Deltalambda), peak wavelength (lambda(0)), and shape of the spectrum on the spectral shifts and spectral switches measured due to temporal correlation in a white-light Michelson interferometer operated in the spectral domain. Behavior of the spectral switch characteristics such as the switch position, switch amplitude, and switch symmetry are discussed in detail as a function of optical path difference between the interfering beams. The experimental results are compared with numerical calculations carried out using interference law in the spectral domain with modified source spectral characteristics. On the basis of our results we feel that our study is of critical importance in the selection of source spectral characteristics to further improve the longitudinal resolution or the measurement sensitivity in spectral-domain optical coherence tomography and microscopy.

  2. Electro-optic modulation of light propagating near the optic axis with any polarization in uniaxial crystals

    Science.gov (United States)

    Song, Zhe; Liu, Liren; Zhou, Yu; Liu, De'an; Ren, Haixia

    2006-09-01

    The electro-optic effect in uniaxial crystals for light propagating near the optic axis with any polarization has been analyzed. The passive and the electrically induced birefringences and the rotation of polarization direction in crystals have been calculated, and the conoscopic interference figures under orthogonal polariscopes for different polarizer directions have been plotted. The extinction areas caused by the rotation of polarization direction in crystals change with the polarizer direction, but the two heads of the induced optical axes do not vary, which are always on the induced principal axis with bigger refractive index. The directions of polariscopes are always extinction, and the +/-45[degree sign] directions with polarizer are always complete transmission. The conoscopic interference figures for LiNbO3 crystals have been demonstrated experimentally by rotating polariscopes directions, which accord with the theoretically calculating plots.

  3. On interstellar light polarization by diamagnetic silicate and carbon dust in the infrared

    Science.gov (United States)

    Papoular, R.

    2018-04-01

    The motion of diamagnetic dust particles in interstellar magnetic fields is studied numerically with several different sets of parameters. Two types of behaviour are observed, depending on the value of the critical number R, which is a function of the grain inertia, the magnetic susceptibility of the material and of the strength of rotation braking. If R ≤ 10, the grain ends up in a static state and perfectly aligned with the magnetic field, after a few braking times. If not, it goes on precessing and nutating about the field vector for a much longer time. Usual parameters are such that the first situation can hardly be observed. Fortunately, in the second and more likely situation, there remains a persistent partial alignment that is far from negligible, although it decreases as the field decreases and as R increases. The solution of the complete equations of motion of grains in a field helps understanding the details of this behaviour. One particular case of an ellipsoidal forsterite silicate grain is studied in detail and shown to polarize light in agreement with astronomical measurements of absolute polarization in the infrared. Phonons are shown to contribute to the progressive flattening of extinction and polarization towards long wavelengths. The measured dielectric properties of forsterite qualitatively fit the Serkowski peak in the visible.

  4. Improving the lifetime in optical microtraps by using elliptically polarized dipole light

    Science.gov (United States)

    Garcia, Sébastien; Reichel, Jakob; Long, Romain

    2018-02-01

    Tightly focused optical dipole traps induce vector light shifts ("fictitious magnetic fields") which complicate their use for single-atom trapping and manipulation. The problem can be mitigated by adding a larger, real magnetic field, but this solution is not always applicable; in particular, it precludes fast switching to a field-free configuration. Here we show that this issue can be addressed elegantly by deliberately adding a small elliptical polarization component to the dipole trap beam. In our experiments with single 87Rb atoms laser-cooled in a chopped trap, we observe improvements up to a factor of 11 of the trap lifetime compared to the standard, seemingly ideal linear polarization. This effect results from a modification of heating processes via spin-state diffusion in state-dependent trapping potentials. We develop Monte Carlo simulations of the evolution of the atom's internal and motional states and find that they agree quantitatively with the experimental data. The method is general and can be applied in all experiments where the longitudinal polarization component is non-negligible.

  5. Highly polarized light from stable ordered magnetic fields in GRB 120308A.

    Science.gov (United States)

    Mundell, C G; Kopač, D; Arnold, D M; Steele, I A; Gomboc, A; Kobayashi, S; Harrison, R M; Smith, R J; Guidorzi, C; Virgili, F J; Melandri, A; Japelj, J

    2013-12-05

    After the initial burst of γ-rays that defines a γ-ray burst (GRB), expanding ejecta collide with the circumburst medium and begin to decelerate at the onset of the afterglow, during which a forward shock travels outwards and a reverse shock propagates backwards into the oncoming collimated flow, or 'jet'. Light from the reverse shock should be highly polarized if the jet's magnetic field is globally ordered and advected from the central engine, with a position angle that is predicted to remain stable in magnetized baryonic jet models or vary randomly with time if the field is produced locally by plasma or magnetohydrodynamic instabilities. Degrees of linear polarization of P ≈ 10 per cent in the optical band have previously been detected in the early afterglow, but the lack of temporal measurements prevented definitive tests of competing jet models. Hours to days after the γ-ray burst, polarization levels are low (P GRBs contain magnetized baryonic jets with large-scale uniform fields that can survive long after the initial explosion.

  6. Polarized light and scanning electron microscopic investigation of enamel hypoplasia in primary teeth.

    Science.gov (United States)

    Sabel, Nina; Klingberg, Gunilla; Dietz, Wolfram; Nietzsche, Sandor; Norén, Jörgen G

    2010-01-01

    Enamel hypoplasia is a developmental disturbance during enamel formation, defined as a macroscopic defect in the enamel, with a reduction of the enamel thickness with rounded, smooth borders. Information on the microstructural level is still limited, therefore further studies are of importance to better understand the mechanisms behind enamel hypoplasia. To study enamel hypoplasia in primary teeth by means of polarized light microscopy and scanning electron microscopy. Nineteen primary teeth with enamel hypoplasia were examined in a polarized light microscope and in a scanning electron microscope. The cervical and incisal borders of the enamel hypoplasia had a rounded appearance, as the prisms in the rounded cervical area of the hypoplasia were bent. The rounded borders had a normal surface structure whereas the base of the defects appeared rough and porous. Morphological findings in this study indicate that the aetiological factor has a short duration and affects only certain ameloblasts. The bottom of the enamel hypoplasia is porous and constitutes possible pathways for bacteria into the dentin.

  7. Bioinspired Mesoporous Chiral Nematic Graphitic Carbon Nitride Photocatalysts modulated by Polarized Light.

    Science.gov (United States)

    Lin, Wensheng; Hong, Wei; Sun, Lu; Yu, Di; Yu, Dingshan; Chen, Xudong

    2018-01-10

    Endowing materials with chirality and exploring the responses of the material under circularly polarized light (CPL) can enable further insight into the physical and chemical properties of the semiconductors to be gained, thus expanding on optoelectronic applications. Herein a bioinspired mesoporous chiral nematic graphitic carbon nitride (g-C 3 N 4 ) for efficient hydrogen evolution with polarized light modulation based on chiral nematic cellulose nanocrystal films prepared through silica templating is described. The mesoporous nematic chiral g-C 3 N 4 exhibits an ultrahigh hydrogen evolution rate of 219.9 μmol h -1 (for 20 mg catalyst), corresponding to a high enhancement factor of 55 when compared to the bulk g-C 3 N 4 under λ>420 nm irradiation. Furthermore, the chiral g-C 3 N 4 material exhibits unique photocatalytic activity modulated by CPL within the absorption region. This CPL-assisted photocatalytic regulation strategy holds great promise for a wide range of applications including optical devices, asymmetric photocatalysis, and chiral recognition/separation. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The "Polar Light Sign" is a useful tool to detect discrete membranous supravalvular mitral stenosis.

    Science.gov (United States)

    Hertwig, Christine; Haas, Nikolaus A; Habash, Sheeraz; Hanslik, Andreas; Kececioglu, Deniz; Sandica, Eugen; Laser, Kai-Thorsten

    2015-02-01

    Mitral valve stenosis caused by a discrete supravalvular membrane is a rare congenital malformation haemodynamically leading to significant mitral valve stenosis. When the supravalvular mitral stenosis consists of a discrete supravalvular membrane adherent to the mitral valve, it is usually not clearly detectable by routine echocardiography. We report about the typical echocardiographic finding in three young patients with this rare form of a discrete membranous supravalvular stenosis caused by a membrane adherent to the mitral valve. These cases present a typical echocardiographic feature in colour Doppler generated by the pathognomonic supramitral flow acceleration. Whereas typical supravalvular mitral stenosis caused by cor triatriatum or a clearly visible supravalvular ring is easily detectable by echocardiography, a discrete supravalvular membrane adjacent to the mitral valve leaflets resembling valvular mitral stenosis is difficult to differentiate by routine echocardiography. In our opinion, this colour phenomenon does resemble the visual impression of polar lights in the northern hemisphere; owing to its typical appearance, it may therefore be named as "Polar Light Sign". This phenomenon may help to detect this anatomical entity by echocardiography in time and therefore improve the prognosis for repair.

  9. Polarized angular dependent light scattering from plasmonic nanoparticles: Modeling, measurements, and biomedical applications

    Science.gov (United States)

    Fu, Kun

    Several significant applications have been realized for light scattering in biomedical imaging. In order to improve imaging results with light scattering-based techniques, a variety of nanoparticles have been investigated as contrast agents, including gold nanoshells. As a method for studying the optical properties of plasmonic gold nanoparticles used as contrast agents for molecular imaging, we developed an automated goniometer instrumentation system. This system, which allows us to specifically study polarized angular-dependent light scattering of plasmonic nanoparticles, allowed us to perform a series of theoretical and experimental step-wise studies. The basic optical properties of the following gold nanoparticles were progressively investigated: (1) bare nanoshells at multipolar plasmonic resonances, (2) nanoshells with PEG modifications, (3) surface-textured nanoshells and (4) immunotargeted nanoshells (nanoshell-antibody bioconjugates) for cancer imaging. Based on the results from these studies, a new technique was developed to quantitatively measure the number of immunotargeted nanoparticles that bind to HER2-positive SKBR3 human breast cancer cells. Preliminary studies of determining the minimal incubation time of immunotargeted nanoshells with SKBR3 cells were also carried out to evaluate the potential clinical application of using gold nanoshells intraoperatively. We, therefore, anticipate that our findings will provide the theoretical groundwork required for further studies aimed at optimizing the application of plasmonic nanoparticles in scattering-based optical imaging techniques.

  10. The effect of polarized polychromatic noncoherent light (bioptron) therapy on patients with carpal tunnel syndrome.

    Science.gov (United States)

    Raeissadat, Seyed Ahmad; Rayegani, Seyed Mansoor; Rezaei, Sajad; Sedighipour, Leyla; Bahrami, Mohammad Hasan; Eliaspour, Dariush; Karimzadeh, Afshin

    2014-01-01

    To study the effects of Polarized Polychromatic Noncoherent Light (Bioptron) therapy on patients with carpal tunnel syndrome (CTS). This study was designed as a randomized clinical trial. Forty four patients with mild or moderate CTS (confirmed by clinical and electrodiagnostic studies) were assigned randomly into two groups (intervention and control goups). At the beginning of the study, both groups received wrist splinting for 8 weeks. Bioptron light was applied for the intervention group (eight sessions, for 3/weeks). Bioptron was applied perpendicularly to the wrist from a 10 centimeter sdistance. Pain severity and electrodiagnostic measurements were compared from before to 8 weeks after initiating each treatment. Eight weeks after starting the treatments, the mean of pain severity based on Visual Analogue Scale (VAS) scores decreased significantly in both groups. Median Sensory Nerve Action Potential (SNAP) latency decreased significantly in both groups. However, other electrophysiological findings (median Compound Motor Action Potential (CMAP) latency and amplitude, also SNAP amplitude) did not change after the therapy in both groups. There was no meaningful difference between two groups regarding the changes in the pain severity. Bioptron with the above mentioned parameters led to therapeutic effects equal to splinting alone in patients with carpal tunnel syndrome. However, applying Bioptron with different therapeutic protocols and light parameters other than used in this study, perhaps longer duration of therapy and long term assessment may reveal different results favoring Bioptron therapy.

  11. Degrees of polarization of reflected light eliciting polarotaxis in dragonflies (Odonata), mayflies (Ephemeroptera) and tabanid flies (Tabanidae).

    Science.gov (United States)

    Kriska, György; Bernáth, Balázs; Farkas, Róbert; Horváth, Gábor

    2009-12-01

    With few exceptions insects whose larvae develop in freshwater possess positive polarotaxis, i.e., are attracted to sources of horizontally polarized light, because they detect water by means of the horizontal polarization of light reflected from the water surface. These insects can be deceived by artificial surfaces (e.g. oil lakes, asphalt roads, black plastic sheets, dark-coloured cars, black gravestones, dark glass surfaces, solar panels) reflecting highly and horizontally polarized light. Apart from the surface characteristics, the extent of such a 'polarized light pollution' depends on the illumination conditions, direction of view, and the threshold p* of polarization sensitivity of a given aquatic insect species. p* means the minimum degree of linear polarization p of reflected light that can elicit positive polarotaxis from a given insect species. Earlier there were no quantitative data on p* in aquatic insects. The aim of this work is to provide such data. Using imaging polarimetry in the red, green and blue parts of the spectrum, in multiple-choice field experiments we measured the threshold p* of ventral polarization sensitivity in mayflies, dragonflies and tabanid flies, the positive polarotaxis of which has been shown earlier. In the blue (450nm) spectral range, for example, we obtained the following thresholds: dragonflies: Enallagma cyathigerum (0%

  12. Polarized light curves illuminate wind geometries in Wolf-Rayet binary stars

    Science.gov (United States)

    Hoffman, Jennifer L.; Fullard, Andrew G.; Nordsieck, Kenneth H.

    2018-01-01

    Although the majority of massive stars are affected by a companion during the course of their evolution, the role of binary systems in creating supernova and GRB progenitors is not well understood. Binaries containing Wolf-Rayet stars are particularly interesting because they may provide a mechanism for producing the rapid rotation necessary for GRB formation. However, constraining the evolutionary fate of a Wolf-Rayet binary system requires characterizing its mass loss and mass transfer, a difficult prospect in systems whose colliding winds obscure the stars and produce complicated spectral signatures.The technique of spectropolarimetry is ideally suited to studying WR binary systems because it can disentangle spectral components that take different scattering paths through a complex distribution of circumstellar material. In particular, comparing the polarization behavior as a function of orbital phase of the continuum (which arises from the stars) with that of the emission lines (which arise from the interaction region) can provide a detailed view of the wind structures in a WR+O binary and constrain the system’s mass loss and mass transfer properties.We present new continuum and line polarization curves for three WR+O binaries (WR 30, WR 47, and WR 113) obtained with the RSS spectropolarimeter at the Southern African Large Telescope. We use radiative transfer simulations to analyze the polarization curves, and discuss our interpretations in light of current models for V444 Cygni, a well-studied related binary system. Accurately characterizing the structures of the wind collision regions in these massive binaries is key to understanding their evolution and properly accounting for their contribution to the supernova (and possible GRB) progenitor population.

  13. Identification of crystals in Hanford nuclear waste using polarized light microscopy

    International Nuclear Information System (INIS)

    Herting, D.L.

    1984-09-01

    The use of polarized light microscopy for identifying crystals encountered in Rockwell Hanford Operations chemical studies is described. Identifying characteristics and full-color photographs are presented for crystals commonly found in Hanford Site nuclear waste, including sodium nitrate, sodium nitrite, sodium aluminate, sodium phosphate, sodium fluoride, ammonium heptafluorozirconate, sodium sulfate, sodium carbonate, and ammonium nitrate. These characteristics are described in terms of birefringence, extinction position, interference figure, sign of elongation, optic sign, and crystal morphology. Background information on crystal optics is presented so that these traits can be understood by the nonmicroscopist. Detailed operational instructions are given so that the novice microscope user can make the proper adjustments of the instrument to search for and observe the identifying features of the crystals

  14. Imaging the response of individual carbon nanotubes to polarized light in aqueous environments

    Science.gov (United States)

    Walker, Bryant; Brintlinger, Todd; Fuhrer, Michael S.; Cumings, John; Hobbie, Erik

    2007-03-01

    Individual carbon nanotubes are grown using chemical vapor deposition (methane-ethylene carrier gas and iron nitrate catalyst), freely suspended in an aqueous solution using a surfactant (sodium dodecyl sulfate), and imaged in an optical microscope using either fluorescent dye (PKH67 and PKH23) or intrinsic near-infrared fluorescence. Freely suspended, individual carbon nanotubes of length 1-8 micrometers show an increasing response to illuminating light as the polarization becomes parallel to tube axis. More intriguingly, some of the carbon nanotubes are found to collapse and fold under 10-30 seconds of illumination, with increasing tube length showing longer time-to-collapse. Unperturbed persistence lengths in these nanotubes are estimated to be 200-300 micrometers.

  15. A New Code SORD for Simulation of Polarized Light Scattering in the Earth Atmosphere

    Science.gov (United States)

    Korkin, Sergey; Lyapustin, Alexei; Sinyuk, Aliaksandr; Holben, Brent

    2016-01-01

    We report a new publicly available radiative transfer (RT) code for numerical simulation of polarized light scattering in plane-parallel atmosphere of the Earth. Using 44 benchmark tests, we prove high accuracy of the new RT code, SORD (Successive ORDers of scattering). We describe capabilities of SORD and show run time for each test on two different machines. At present, SORD is supposed to work as part of the Aerosol Robotic NETwork (AERONET) inversion algorithm. For natural integration with the AERONET software, SORD is coded in Fortran 90/95. The code is available by email request from the corresponding (first) author or from ftp://climate1.gsfc.nasa.gov/skorkin/SORD/.

  16. Circularly polarized reflection from the scarab beetle Chalcothea smaragdina: light scattering by a dual photonic structure.

    Science.gov (United States)

    McDonald, Luke T; Finlayson, Ewan D; Wilts, Bodo D; Vukusic, Pete

    2017-08-06

    Helicoidal architectures comprising various polysaccharides, such as chitin and cellulose, have been reported in biological systems. In some cases, these architectures exhibit stunning optical properties analogous to ordered cholesteric liquid crystal phases. In this work, we characterize the circularly polarized reflectance and optical scattering from the cuticle of the beetle Chalcothea smaragdina (Coleoptera: Scarabaeidae: Cetoniinae) using optical experiments, simulations and structural analysis. The selective reflection of left-handed circularly polarized light is attributed to a Bouligand-type helicoidal morphology within the beetle's exocuticle. Using electron microscopy to inform electromagnetic simulations of this anisotropic stratified medium, the inextricable connection between the colour appearance of C. smaragdina and the periodicity of its helicoidal rotation is shown. A close agreement between the model and the measured reflectance spectra is obtained. In addition, the elytral surface of C. smaragdina possesses a blazed diffraction grating-like surface structure, which affects the diffuse appearance of the beetle's reflected colour, and therefore potentially enhances crypsis among the dense foliage of its rainforest habitat.

  17. A dead-zone free ⁴He atomic magnetometer with intensity-modulated linearly polarized light and a liquid crystal polarization rotator.

    Science.gov (United States)

    Wu, T; Peng, X; Lin, Z; Guo, H

    2015-10-01

    We demonstrate an all-optical (4)He atomic magnetometer experimental scheme based on an original Bell-Bloom configuration. A single intensity-modulated linearly polarized laser beam is used both for generating spin polarization within a single (4)He vapor and probing the spin precessing under a static magnetic field. The transmitted light signal from the vapor is then phase-sensitively detected at the modulation frequency and its harmonics, which lead to the atomic magnetic resonance signals. Based on this structure, a liquid crystal is added in our magnetometer system and constitutes a polarization rotator. By controlling the voltage applied on the liquid crystal, the light linear polarization vector can be kept perpendicular with the ambient magnetic field direction, which in turn provides the maximum resonance signal amplitude. Moreover, the system exhibits a magnetic-field noise floor of about 2pT/√Hz, which is not degraded due to the presence of the liquid crystal and varying magnetic field direction. The experiment results prove that our method can eliminate the dead-zone effect, improve the system spatial isotropy, and thus be suitable in mobile applications.

  18. Study of Photosensitivity as a Function of Polarization for UV-Light in Optical Fibre using Blue Luminescence

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Canning, John; Gregersen, Niels

    2005-01-01

    The difference in photosensitivity between S and P polarized light is investigated. Polarisation dependent scattering at the fibre-air surface and UV-induced alignment are shown to be of no importance, but indications of radially parasitic defects sites are found.......The difference in photosensitivity between S and P polarized light is investigated. Polarisation dependent scattering at the fibre-air surface and UV-induced alignment are shown to be of no importance, but indications of radially parasitic defects sites are found....

  19. The opioid fentanyl affects light input, electrical activity and Per gene expression in the hamster suprachiasmatic nuclei.

    Science.gov (United States)

    Vansteensel, Mariska J; Magnone, Maria Chiara; van Oosterhout, Floor; Baeriswyl, Stéphanie; Albrecht, Urs; Albus, Henk; Dahan, Albert; Meijer, Johanna H

    2005-06-01

    The suprachiasmatic nuclei (SCN) contain a major circadian pacemaker, which is regulated by photic and nonphotic stimuli. Although enkephalins are present in the SCN, their role in phase regulation of the pacemaker is largely unknown. The opioid agonist fentanyl, a homologue of morphine, is an addictive drug that induces phase shifts of circadian rhythms in hamsters. We observed that these phase shifts are blocked by naloxone, which is a critical test for true opioid receptor involvement, and conclude that opioid receptors are the sole mediators of the actions of fentanyl on the circadian timing system. A strong interaction between opioids and light input was shown by the ability of fentanyl and light to completely block each other's phase shifts of behavioural activity rhythms. Neuronal ensemble recordings in vitro provide first evidence that SCN cells show direct responses to fentanyl and react with a suppression of firing rate. Moreover, we show that fentanyl induces a strong attenuation of light-induced Syrian hamster Period 1 (shPer1) gene expression during the night. During the subjective day, we found no evidence for a role of shPer1 in mediation of fentanyl-induced phase shifts. Based on the present results, however, we cannot exclude the involvement of shPer2. Our data indicate that opioids can strongly modify the photic responsiveness of the circadian pacemaker and may do so via direct effects on SCN electrical activity and regulation of Per genes. This suggests that the pathways regulating addictive behaviour and the circadian clock intersect.

  20. Polarized light transmission in ferrofluids loaded with carbon nanotubes in the presence of a uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Vales-Pinzón, C., E-mail: cvales@mda.cinvestav.mx [Applied Physics Department, CINVESTAV-Unidad Mérida, Antigua carretera a Progreso km 6, A.P. 73, Cordemex, Mérida Yucatán 97310 (Mexico); Alvarado-Gil, J.J. [Applied Physics Department, CINVESTAV-Unidad Mérida, Antigua carretera a Progreso km 6, A.P. 73, Cordemex, Mérida Yucatán 97310 (Mexico); Medina-Esquivel, R. [Facultad de Ingeniería-UADY, Av. Industrias no Contaminantes por Periférico Norte, A.P. 150, Cordemex, Mérida, Yucatán (Mexico); Martínez-Torres, P. [Department of Mechanical Engineering, University of California, Riverside, 900 University Ave., Riverside, CA 92521 (United States)

    2014-11-15

    Magneto-optic phenomena in ferrofluids have been shown to be related to the formation of chain structures, due to the arrangement of the ferromagnetic particles, induced by an applied magnetic field. In this work, the effects on transmission of polarized light due to anisotropic effects induced by an external magnetic field in ferrofluids with carbon nanotubes are studied. The time response of the system presents two well defined stages, in the first one, which is very short, the fluid behaves as a polarizer. In contrast in the second stage, the effects of light transmission dominate. In this stage the transmitted light intensity grows with time and after a long time reaches a constant stable value. It is shown that these phenomena depend on the carbon nanotubes concentration as well as on the strength of the applied magnetic field. Using a simple model that considers a chain-like structure formation, it is possible to determine the rate of agglomeration of the formed structures and the attenuation coefficient of the transmitted light. The formation of nanostructures leads to variation in the transmitted light, depending on the polarization of the incident light. These magnetic nanostructures can find numerous applications in nanotechnology, optical devices and medicine. - Highlights: • Carbon nanotubes in ferrofluids favor the formation of chain-like structures. • In the presence of a magnetic field ferrofluids loaded with CNT behaves as a polarizer. • Transmitted light increases when samples are under a magnetic field then stabilizes. • Attenuation time for transmitted light and agglomeration parameters were studied.

  1. Strongly transverse-electric-polarized emission from deep ultraviolet AlGaN quantum well light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Reich, Christoph, E-mail: Christoph.Reich@tu-berlin.de; Guttmann, Martin; Wernicke, Tim; Mehnke, Frank; Kuhn, Christian [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, Berlin 10623 (Germany); Feneberg, Martin; Goldhahn, Rüdiger [Institut für Experimentelle Physik, Otto-von-Guericke-Universität, Universitätsplatz 2, Magdeburg 39106 (Germany); Rass, Jens; Kneissl, Michael [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, Berlin 10623 (Germany); Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany); Lapeyrade, Mickael; Einfeldt, Sven; Knauer, Arne; Kueller, Viola; Weyers, Markus [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany)

    2015-10-05

    The optical polarization of emission from ultraviolet (UV) light emitting diodes (LEDs) based on (0001)-oriented Al{sub x}Ga{sub 1−x}N multiple quantum wells (MQWs) has been studied by simulations and electroluminescence measurements. With increasing aluminum mole fraction in the quantum well x, the in-plane intensity of transverse-electric (TE) polarized light decreases relative to that of the transverse-magnetic polarized light, attributed to a reordering of the valence bands in Al{sub x}Ga{sub 1−x}N. Using k ⋅ p theoretical model calculations, the AlGaN MQW active region design has been optimized, yielding increased TE polarization and thus higher extraction efficiency for bottom-emitting LEDs in the deep UV spectral range. Using (i) narrow quantum wells, (ii) barriers with high aluminum mole fractions, and (iii) compressive growth on patterned aluminum nitride sapphire templates, strongly TE-polarized emission was observed at wavelengths as short as 239 nm.

  2. [Sensory and electrical responses in stimulation of the macula with short-wave (407-527 nm) linear polarized light (Haidinger polarization brushes)].

    Science.gov (United States)

    Dodt, E; Tsuyama, Y; Kuba, M

    1994-04-01

    We investigated Haidinger's (1844) entoptic polarization brushes of the macula psychophysically and electrophysiologically during rotation of plane-polarized blue (projected to a polarization screen. Psychophysically the sensitivity of the brushes was highest between 470 and 490 nm, with a steep decrease at longer wavelengths. Increase of adaptive illumination (I) above 0.1 cd/m2 increased the increment threshold (delta I) of the brushes between 407 and 515 nm about equally (delta I/I = 0.9). Comparison of the action spectrum of different photoreceptors with the spectral sensitivity of Haidinger's brushes suggested synergistic contributions of blue, green and red photoreceptors. A decrease in visual acuity to 0.01 by plus lenses did not affect the light threshold of the brushes significantly, while blurring by Bangerter foils increased the threshold markedly (about eightfold at visual acuity of 0.01). Thus, the determination of threshold of Haidinger's brushes provides the means of investigating certain macular functions behind, and widely independent of, opacities of the ocular media. While no retinal potentials (ERG) were seen during rotation of the polarizer, we obtained cortical potentials (VEP) closely related to the appearance of Haidinger's brushes in response to rotation onset of blue polarized light. The potential derived from Oz+Ol+Or consisted of a phasic negative response after a peak latency of 295 +/- 34 ms (N 295). Similar responses were also obtained to medium and long wavelengths (extrinsic windmill rotation during foveal fixation at stimulus conditions closely related to Haidinger's brushes: 3 degrees field, 2 cy/rev, 2 cd/m2, contrast 0.15). Thus VEP recording permits the comparison of entoptic and extrinsic excitation of the macula.

  3. Photobiomodulation with polarized light in the treatment of cutaneous and mucosal ulcerative lesions.

    Science.gov (United States)

    Aragona, S E; Grassi, F R; Nardi, G; Lotti, J; Mereghetti, G; Canavesi, E; Equizi, E; Puccio, A M; Lotti, T

    In recent decades, regenerative medicine has achieved an important evolution at both a conceptual level and scientific production, which explains the current and future possibilities of therapy and daily clinical practice. The main aim of regenerative medicine is the complex system of repair/regeneration. The current literature on the subject demonstrates the advantage of visible light therapy for skin injuries and diseases with the photobiomodulation in which light at low energy levels modulates intra- and extra-cellular photoreceptors by molecular and cellular processes that can stimulate both anti-inflammatory mechanisms and cell proliferative response. The irradiation effects are activated soon after exposure. The anti-inflammatory action on some classes of cytokines and cells (e.g. mast cells and macrophages) is completed with the stimulation of the nitric oxide production, which has an anti-inflammatory and vasodilation action, and gives analgesic relief. Our attention focused on photobiomodulator medical device emitting polarized light. 30 patients (19 women and 11 men) were enrolled in the present study. They were treated for chronic lesions using Bioptron® Light Therapy System device. Patients were initially subjected to Bioptron® light for 20 min after cleansing of the lesion. The operating protocol provides 24 sessions: twice per week for 12 weeks. Twenty patients have been studied for symptoms, histological samples and ulcer characteristics. After 2 months, a reduction of 50% of the lesions was recorded in 18 patients (60%), while in the remaining patients a slower healing was observed. The total wound healing was achieved after 3 months in 13 patients (43%). The examined parameters of the symptom were exudation, pain and signs of infection. Results at 1 and 3 months were, Exudation: at 1 month reduction and positive modulation was observed in 16 patients (53%) and in 25 patients at 3 months; Pain: (evaluated with Vas scale), decreased in 21 patients

  4. The use of charge extraction by linearly increasing voltage in polar organic light-emitting diodes

    Science.gov (United States)

    Züfle, Simon; Altazin, Stéphane; Hofmann, Alexander; Jäger, Lars; Neukom, Martin T.; Schmidt, Tobias D.; Brütting, Wolfgang; Ruhstaller, Beat

    2017-05-01

    We demonstrate the application of the CELIV (charge carrier extraction by linearly increasing voltage) technique to bilayer organic light-emitting devices (OLEDs) in order to selectively determine the hole mobility in N,N0-bis(1-naphthyl)-N,N0-diphenyl-1,10-biphenyl-4,40-diamine (α-NPD). In the CELIV technique, mobile charges in the active layer are extracted by applying a negative voltage ramp, leading to a peak superimposed to the measured displacement current whose temporal position is related to the charge carrier mobility. In fully operating devices, however, bipolar carrier transport and recombination complicate the analysis of CELIV transients as well as the assignment of the extracted mobility value to one charge carrier species. This has motivated a new approach of fabricating dedicated metal-insulator-semiconductor (MIS) devices, where the extraction current contains signatures of only one charge carrier type. In this work, we show that the MIS-CELIV concept can be employed in bilayer polar OLEDs as well, which are easy to fabricate using most common electron transport layers (ETLs), like Tris-(8-hydroxyquinoline)aluminum (Alq3). Due to the macroscopic polarization of the ETL, holes are already injected into the hole transport layer below the built-in voltage and accumulate at the internal interface with the ETL. This way, by a standard CELIV experiment only holes will be extracted, allowing us to determine their mobility. The approach can be established as a powerful way of selectively measuring charge mobilities in new materials in a standard device configuration.

  5. Polarity-Tunable Host Materials and Their Applications in Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes.

    Science.gov (United States)

    Xie, Gaozhan; Chen, Dongjun; Li, Xianglong; Cai, Xinyi; Li, Yunchuan; Chen, Dongcheng; Liu, Kunkun; Zhang, Qian; Cao, Yong; Su, Shi-Jian

    2016-10-04

    A series of polarity-tunable host materials were developed based on oligocarbazoles and diphenylphosphine oxide, and their polarities can be tuned through increasing distance of acceptor and donor units. Density functional theory calculations were employed, and photoluminescence spectra in different polar solvents were measured to illustrate different polarities of these host materials. As CZPO has relatively stronger polarity, electroluminescence (EL) spectrum of solution-processed device based on 6 wt % PXZDSO2:CZPO is 7 nm red-shifted relative to that of other host materials based devices. Besides, a comparable impressive external quantum efficiency (EQE) value of 18.7% is achieved for an evaporation-processed yellow device consisting of FCZBn, which is superior to that of the device based on CBP (4,4'-dicarbazolyl-1,1'-biphenyl) (17.0%), and its efficiency roll-off is also obviously reduced, giving an EQE value as high as 16.3% at the luminance of 1000 cd/m 2 . In addition, from CZPO to FCZBn as the polarities of host materials decrease, EL spectra of solution-processed devices based on DMAC-DPS emitter blue-shift constantly from 496 to 470 nm. The current work gives a constructive approach to control EL spectra of organic light-emitting diodes with a fixed thermally activated delayed fluorescence emitter by tuning the polarities of host materials.

  6. Polarization-sensitive optical frequency domain imaging based on unpolarized light

    NARCIS (Netherlands)

    Kim, K.H.; Park, B. H.; Tu, Y.P.; Hasan, T.; Lee, B.; Li, J.; de Boer, J.F.

    2011-01-01

    Polarization-sensitive optical coherence tomography (PS-OCT) is an augmented form of OCT, providing 3D images of both tissue structure and polarization properties. We developed a new method of polarization-sensitive optical frequency domain imaging (PS-OFDI), which is based on a wavelength-swept

  7. Quantitative characterization of the carbon/carbon composites components based on video of polarized light microscope.

    Science.gov (United States)

    Li, Yixian; Qi, Lehua; Song, Yongshan; Chao, Xujiang

    2017-06-01

    The components of carbon/carbon (C/C) composites have significant influence on the thermal and mechanical properties, so a quantitative characterization of component is necessary to study the microstructure of C/C composites, and further to improve the macroscopic properties of C/C composites. Considering the extinction crosses of the pyrocarbon matrix have significant moving features, the polarized light microscope (PLM) video is used to characterize C/C composites quantitatively because it contains sufficiently dynamic and structure information. Then the optical flow method is introduced to compute the optical flow field between the adjacent frames, and segment the components of C/C composites from PLM image by image processing. Meanwhile the matrix with different textures is re-segmented by the length difference of motion vectors, and then the component fraction of each component and extinction angle of pyrocarbon matrix are calculated directly. Finally, the C/C composites are successfully characterized from three aspects of carbon fiber, pyrocarbon, and pores by a series of image processing operators based on PLM video, and the errors of component fractions are less than 15%. © 2017 Wiley Periodicals, Inc.

  8. High-speed polarized light microscopy for in situ, dynamic measurement of birefringence properties

    Science.gov (United States)

    Wu, Xianyu; Pankow, Mark; Shadow Huang, Hsiao-Ying; Peters, Kara

    2018-01-01

    A high-speed, quantitative polarized light microscopy (QPLM) instrument has been developed to monitor the optical slow axis spatial realignment during controlled medium to high strain rate experiments at acquisition rates up to 10 kHz. This high-speed QPLM instrument is implemented within a modified drop tower and demonstrated using polycarbonate specimens. By utilizing a rotating quarter wave plate and a high-speed camera, the minimum acquisition time to generate an alignment map of a birefringent specimen is 6.1 ms. A sequential analysis method allows the QPLM instrument to generate QPLM data at the high-speed camera imaging frequency 10 kHz. The obtained QPLM data is processed using a vector correlation technique to detect anomalous optical axis realignment and retardation changes throughout the loading event. The detected anomalous optical axis realignment is shown to be associated with crack initiation, propagation, and specimen failure in a dynamically loaded polycarbonate specimen. The work provides a foundation for detecting damage in biological tissues through local collagen fiber realignment and fracture during dynamic loading.

  9. Polarized light microscopic analysis of bone formation after inhibition of cyclooxygenase 1 and 2.

    Science.gov (United States)

    Retamoso, Luciana Borges; Montagner, Francisco; Camargo, Elisa Souza; Vitral, Roberto Willer Farinazzo; Tanaka, Orlando Motohiro

    2010-02-01

    Potassium diclofenac is a potent nonsteroidal anti-inflammatory drug (NSAID) and COX isoforms (COX-1 and COX-2) inhibitor. Quantitative analysis of birefringence with polarized light microscopy is a useful method to investigate the macromolecular orientation and organization of collagen fibers in connective tissues. The aim of this research was to analyze the collagen structure and maturation in bone formed after potassium diclofenac administration, during first molar orthodontic movement. Sixty Wistar rats were divided in two equal groups (N = 30): control (C) and potassium diclofenac (PD). The animals in Group C received 0.9% saline solution and the PD group received potassium diclofenac Cataflam (5 mg/kg). Animals were sacrificed 3, 7, or 14 days after a NiTi unilateral closed-coil spring was stretched between the upper right first molar and the incisors. The first molar area was fixed, decalcified, and histologically processed using picrosirius pigment. The collagen birefringence of bone turnover was analyzed by phase retardation. Two-way ANOVA and Tukey's test showed that optical retardation was influenced by time and treatment. There was increase in the collagen organization over time. On the third day, the C group showed better collagen organization than the PD group. Potassium diclofenac interfered in collagen maturation, reducing fibril organization in the initial phase of orthodontic movement. 2009 Wiley-Liss, Inc.

  10. Effects of Linear-Polarized Near-Infrared Light Irradiation on Chronic Pain

    Directory of Open Access Journals (Sweden)

    Dong Huang

    2012-01-01

    Full Text Available In order to study the efficacy of linear-polarized near-infrared light irradiation (LPNIR on relieving chronic pain in conjunction with nerve block (NB or local block (LB, a 3-week prospective, randomized, double-blind, controlled study was conducted to evaluate the pre- and post-therapy pain intensity. Visual analogue scales (VASs were measured in all patients before and 6 months after therapy visiting the pain clinic during the period of August 2007 to January 2008. A total of 52 patients with either shoulder periarthritis or myofascial pain syndrome or lateral epicondylitis were randomly assigned into two groups by drawing lots. Patients in Group I were treated with NB or LB plus LPNIR; Group II patients, for their part, were treated with the same procedures as in Group I, but not using LPNIR. In both groups, the pain intensity (VAS score decreased significantly immediately after therapy as compared to therapy. There was a significant difference between the test and control groups immediately after therapy (P<0.05, while no effect 6 months later. No side effects were observed. It is concluded that LPNIR is an effective and safe modality to treat various chronic pains, which has synergic effects with NB or LB.

  11. Chiral Nematic Structure of Cellulose Nanocrystal Suspensions and Films; Polarized Light and Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Derek G. Gray

    2015-11-01

    Full Text Available Cellulosic liquid crystalline solutions and suspensions form chiral nematic phases that show a rich variety of optical textures in the liquid crystalline state. These ordered structures may be preserved in solid films prepared by evaporation of solvent or suspending medium. Film formation from aqueous suspensions of cellulose nanocrystals (CNC was investigated by polarized light microscopy, optical profilometry and atomic force microscopy (AFM. An attempt is made to interpret qualitatively the observed textures in terms of the orientation of the cellulose nanocrystals in the suspensions and films, and the changes in orientation caused by the evaporative process. Mass transfer within the evaporating droplet resulted in the formation of raised rings whose magnitude depended on the degree of pinning of the receding contact line. AFM of dry films at short length scales showed a radial orientation of the CNC at the free surface of the film, along with a radial height variation with a period of approximately P/2, ascribed to the anisotropic shrinkage of the chiral nematic structure.

  12. [Polarized light microscopy for evaluation of oocytes as a prognostic factor in the evolution of a cycle in assisted reproduction].

    Science.gov (United States)

    González-Ortega, C; Cancino-Villarreal, P; Alonzo-Torres, V E; Martínez-Robles, I; Pérez-Peña, E; Gutiérrez-Gutiérrez, A M

    2016-04-01

    Identification of the best embryos to transfer is a key element for success in assisted reproduction. In the last decade, several morphological criteria of oocytes and embryos were evaluated with regard to their potential for predicting embryo viability. The introduction of polarization light microscopy systems has allowed the visualization of the meiotic spindle and the different layers of the zona pellucida in human oocytes on the basis of birefringence in a non-destructive way. Conflicting results have been reported regarding the predictive value in ICSI cycles. To assess the predictive ability of meiotic spindle and zona pellucida of human oocytes to implant by polarized microscopy in ICSI cycles. Prospective and observational clinical study. 903 oocytes from 94 ICSI cycles were analyzed with polarized microscopy. Meiotic spindle visualization and zona pellucida birefringence values by polarized microscopy were correlated with ICSI cycles results. Meiotic spindle visualization and birefringence values of zona pellucida decreased in a direct basis with increasing age. In patients aged over the 35 years, the percentage of a visible spindle and mean zona pellucida birefringence was lower than in younger patients. Fertilization rate were higher in oocytes with visible meiotic spindle (81.3% vs. 64%; p < 0.0001), as well as embryo quality (47.4% vs. 39%; p=0.01). Fertilization rate was higher in oocytes with positive values of birefringence (77.5 % vs. 68.5% p=0.005) with similar embryo quality. Conception cycles showed oocytes with higher mean value of zona birefringence and visible spindle vs. no-conception cycles (p<0.05). Polarized light microscopy improves oocyte selection, which significantly impacts in the development of embryos with greater implantation potential. The use of polarized light microscopy with sperm selection methods, blastocyst culture and deferred embryo transfers will contribute to transfer fewer embryos without diminishing rates of live

  13. Powder agglomeration study in RF silane plasmas by in situ polarization-sensitive laser light scattering and TEM measurements

    International Nuclear Information System (INIS)

    Courteille, C.; Hollenstein, C.; Dorier, J.L.; Gay, P.; Schwarzenbach, W.; Howling, A.A.; Bertran, E.; Viera, G.; Martins, R.; Macarico, A.

    1966-03-01

    To determine self-consistently the time evolution of particle size and their number density in situ multi-angle polarization laser light scattering was used. Cross-polarization intensities (incident and scattered light intensities with opposite polarization) measured at 135 o and ex-situ TEM analysis demonstrate the existence of non-spherical agglomerates during the early phase of agglomeration. Later in the particle time development both techniques reveal spherical particles again. The presence of strong cross-polarization intensities is accompanied by low frequency instabilities detected on the scattered light intensities and plasma emission. It is found that the particle radius and particle number density during the agglomeration phase can be well described by the Brownian Free Molecule Coagulation model. Application of this neutral particle coagulation model is justified by calculation of the particle charge whereby it is shown that particles of a few tens of nanometer can be considered as neutral under our experimental conditions. The measured particle dispersion can be well described by a Brownian Free Molecule Coagulation model including a log-normal particle size distribution. (author) 11 figs., 48 refs

  14. Assessment of laser photobiomodulation and polarized light on the healing of cutaneous wounds on euthyroid and hypothyroid induced rats

    Science.gov (United States)

    Ramalho, Luciana Maria Pedreira; Weyll, Barbara Mayoral Pedroso; da Costa Lino, Maíra Dória M.; Ramalho, Maria Jose Pedreira; Barbosa Pinheiro, Antonio Luis

    2010-02-01

    The aim of this study was to assess the influence of low-level laser therapy (LLLT) or polarized light (PL) in cutaneous wound healing of hypothyroid rats at dosages of 20 or 40J/cm2. Bioestimulatory effects of Laser radiation and Polarized light are recognized alternative therapies to improve healing on systemic disease patients, but their usefulness in the improvement of hypothyroidism healing impairment is uncertain till date. Forty Wistar rats were used in this study. Hypothyroidism was propylthiouracil- induced. Standard excisional cutaneous wounds were created without suturing and LLLT (λ660nm, 30mW, φ 3mm) or PL (λ 400-2000nm, 40mW, φ 10mm) was applied every 48 hours up to seven days on experimental groups. The rats were killed on the eighth day when wound contraction was assessed. The healing features were evaluated by light microscopy (H/E and Sirius Red). The cutaneous wounds of hypothyroid rats showed delayed healing process characterized by reduced thickness of epithelial layers, incipient formation of disorganized collagen fibers and wound contraction to a lesser extent (FISHER, p=0.0276), when compared to the euthyroid group. The use of both the Laser and Polarized Light on hypothyroid rats increased the amount of fibroblasts and the thickness of collagen fibers, especially on the L 20J/cm2 group. Euthyroid rats have still demonstrated more regular collagen fibers pattern than hypothyroid rats. It was therefore concluded that hypothyroidism delays wound healing and both Laser photobiomodulation and Polarized Light at 20j/cm2 dosages had improved the healing process in hypothyroid rats.

  15. Comparison of effects of Cyriax physiotherapy, a supervised exercise programme and polarized polychromatic non-coherent light (Bioptron light) for the treatment of lateral epicondylitis.

    Science.gov (United States)

    Stasinopoulos, Dimitrios; Stasinopoulos, Ioannis

    2006-01-01

    To compare the effectiveness of Cyriax physiotherapy, a supervised exercise programme, and polarized polychromatic non-coherent light (Bioptron light) in the treatment of lateral epicondylitis. Controlled clinical trial. Rheumatology and rehabilitation centre. This study was carried out with 75 patients who had lateral epicondylitis. They were allocated to three groups by sequential allocation. Group A (n = 25) was treated with Cyriax physiotherapy. A supervised exercise programme was given to group B (n = 25). Group C (n = 25) received polarized polychromatic non-coherent light (Bioptron light). All patients received three treatments per week for four weeks. Pain was evaluated using a visual analogue scale and function using a visual analogue scale and pain-free grip strength at the end of the four-week course of treatment (week 4), one month (week 8), three months (week 16) and six months (week 28) after the end of treatment. The supervised exercise programme produced the largest effect in the reduction of pain and in the improvement of function at the end of the treatment (PBioptron light) may be suitable.

  16. All-optical 2-to-4 level encoder based on cross polarization modulation in a semiconductor optical amplifier utilized to develop an all-optical 2 input digital multiplexer.

    Science.gov (United States)

    Soto, Horacio; Gutiérrez, Adrian

    2006-10-02

    An all-optical 2-to-4 level encoder based on cross polarization modulation in a semiconductor optical amplifier utilized to develop a 2 input digital multiplexer is presented. The most important feature of this device is the potential it has to improve the use of the available channel bandwidth on communications systems on an all-optical environment.

  17. The impact of bright artificial white and 'blue-enriched' light on sleep and circadian phase during the polar winter.

    Science.gov (United States)

    Mottram, Victoria; Middleton, Benita; Williams, Peter; Arendt, Josephine

    2011-03-01

    Delayed sleep phase (and sometimes free-run) is common in the Antarctic winter (no natural sunlight) and optimizing the artificial light conditions is desirable. This project evaluated sleep when using 17,000 K blue-enriched lamps compared with standard white lamps (5000 K) for personal and communal illumination. Base personnel, 10 males, five females, 32.5±8 years took part in the study. From 24 March to 21 September 2006 light exposure alternated between 4-5-week periods of standard white (5000 K) and blue-enriched lamps (17,000 K), with a 3-week control before and after extra light. Sleep and light exposure were assessed by actigraphy and sleep diaries. General health (RAND 36-item questionnaire) and circadian phase (urinary 6-sulphatoxymelatonin rhythm) were evaluated at the end of each light condition. Direct comparison (rmanova) of blue-enriched light with white light showed that sleep onset was earlier by 19 min (P=0.022), and sleep latency tended to be shorter by 4 min (P=0.065) with blue-enriched light. Analysing all light conditions, control, blue and white, again provided evidence for greater efficiency of blue-enriched light compared with white (Plight conditions. Circadian phase was earlier on average in midwinter blue compared with midwinter white light by 45 min (PLight condition had no influence on general health. We conclude that the use of blue-enriched light had some beneficial effects, notably earlier sleep, compared with standard white light during the polar winter. © 2010 European Sleep Research Society.

  18. Erosion Potential of Tooth Whitening Regimens as Evaluated with Polarized Light Microscopy.

    Science.gov (United States)

    Brambert, Patrick; Qian, Fang; Kwon, So Ran

    2015-11-01

    Tooth whitening is a widely utilized esthetic treatment in dentistry. With increased access to over-the-counter (OTC) systems concerns have been raised as to potential adverse effects associated with overuse of whitening materials. Therefore, this study aimed to evaluate enamel erosion due to different whitening regimens when used in excess of recommended guidelines. Extracted human teeth (n = 66) were randomly divided into 11 groups (n = 6/group). Specimens were exposed to OTC products: Crest Whitestrips and 5-minute natural white and a do-it-yourself (DIY) strawberry whitening recipe. Within each regimen, groups were further divided per exposure time: specimens receiving the recommended product dosage; 5 times the recommended dosage; and 10 times the recommended dosage. Negative and positive controls were treated with grade 3 water and 1.0% citric acid, respectively. Specimens were nail-varnished to limit application to a 1 × 4 mm window. Following treatment, specimens were sectioned and erosion (drop in μm) measured using polarized light microscopy. Two-sample t-test was used to detect difference in amount of enamel erosion between negative and positive groups, while one-way analysis of variance (ANOVA), followed by post hoc Dunnett's test was used to detect difference between set of treatment groups and negative control groups or among all experimental groups. There was significant difference in mean amount of enamel erosion (p erosion for positive control group was significantly greater than that for negative control group (23.50 vs 2.65 μm). There was significant effect for type of treatments on enamel erosion [F(9,50) = 25.19; p 0.05 for all instances), except for Natural White_10 times treatment group (p erosion. Enamel erosion due to the overuse of whitening products varies for different modalities and products. Therefore, caution is advised when using certain over-the-counter products beyond recommended guidelines, as there is potential for enamel

  19. Linearly polarized light emission from InGaN/GaN quantum well structure with high indium composition.

    Science.gov (United States)

    Song, Hooyoung; Kim, Eun Kyu; Han, Il Ki; Lee, Sung-Ho; Hwang, Sung-Min

    2011-10-01

    We fabricated yellow (575 nm) emitting a-plane InGaN/GaN light emitting diode (LED). Microstructure and stress relaxation of the InGaN well layer were observed from the images of dark field transmission electron microscopy. The LED chip was operated at 3.7 V, 20 mA, and the polarization-free characteristic in nonpolar InGaN layer was confirmed from a small blue-shift of approximaely 1.7 nm with increase of current density. The high photoluminescence (PL) efficiency of 30.4% showed that this non-polar InGaN layer has a potential of application to green-red long wavelength light emitters. The PL polarization ratio at 290 K was 0.25 and the energy difference between two subbands was estimated to be 40.2 meV. The low values of polarization and energy difference were due to the stress relaxation of InGaN well layer.

  20. Polarized scattered light from self-luminous exoplanets : Three-dimensional scattering radiative transfer with ARTES

    NARCIS (Netherlands)

    Stolker, T.; Min, M.; Stam, D.M.; Mollière, P.; Dominik, C.; Waters, L. B.F.M.

    2017-01-01

    Context. Direct imaging has paved the way for atmospheric characterization of young and self-luminous gas giants. Scattering in a horizontally-inhomogeneous atmosphere causes the disk-integrated polarization of the thermal radiation to be linearly polarized, possibly detectable with the newest

  1. Impact of light polarization on photoluminescence intensity and quantum efficiency in AlGaN and AlInGaN layers

    Science.gov (United States)

    Netzel, C.; Knauer, A.; Weyers, M.

    2012-12-01

    We analyzed emission intensity, quantum efficiency, and emitted light polarization of c-plane AlGaN and AlInGaN layers (λ = 320-350 nm) by temperature dependent photoluminescence. Low indium content in AlInGaN structures causes a significant intensity increase by change of the polarization of the emitted light. Polarization changes from E ⊥ c to E ‖ c with increasing aluminum content. It switches back to E ⊥ c with the incorporation of indium. The polarization degree decreases with temperature. This temperature dependence can corrupt internal quantum efficiency determination by temperature dependent photoluminescence.

  2. Photo double ionization of helium 100 eV and 450 eV above threshold: II. Circularly polarized light

    International Nuclear Information System (INIS)

    Knapp, A; Kheifets, A; Bray, I; Weber, Th; Landers, A L; Schoessler, S; Jahnke, T; Nickles, J; Kammer, S; Jagutzki, O; Schmidt, L Ph H; Schoeffler, M; Osipov, T; Prior, M H; Schmidt-Boecking, H; Cocke, C L; Doerner, R

    2005-01-01

    We present a joint experimental and theoretical study of the fully differential cross section of the photo double ionization of helium with left and right circularly polarized light at E exc = 100 eV and 450 eV above the threshold. We analyse angular distributions for the slow electron and the normalized circular dichroism for various energy sharings of the excess energy between the two electrons. The experimental results are well reproduced by convergent close coupling calculations

  3. Nonlinear unitary transformations of space-variant polarized light fields from self-induced geometric-phase optical elements

    Science.gov (United States)

    Kravets, Nina; Brasselet, Etienne

    2018-01-01

    We propose to couple the optical orientational nonlinearities of liquid crystals with their ability to self-organize to tailor them to control space-variant-polarized optical fields in a nonlinear manner. Experimental demonstration is made using a liquid crystal light valve that behaves like a light-driven geometric phase optical element. We also unveil two original nonlinear optical processes, namely self-induced separability and nonseparability. These results contribute to the advancement of nonlinear singular optics that is still in its infancy despite 25 years of effort, which may foster the development of nonlinear protocols to manipulate high-dimensional optical information both in the classical and quantum regimes.

  4. Polarization Switching and Light-Enhanced Piezoelectricity in Lead Halide Perovskites.

    Science.gov (United States)

    Coll, Mariona; Gomez, Andrés; Mas-Marza, Elena; Almora, Osbel; Garcia-Belmonte, Germà; Campoy-Quiles, Mariano; Bisquert, Juan

    2015-04-16

    We investigate the ferroelectric properties of photovoltaic methylammonium lead halide CH3NH3PbI3 perovskite using piezoelectric force microscopy (PFM) and macroscopic polarization methods. The electric polarization is clearly observed by amplitude and phase hysteresis loops. However, the polarization loop decreases as the frequency is lowered, persisting for a short time only, in the one second regime, indicating that CH3NH3PbI3 does not exhibit permanent polarization at room temperature. This result is confirmed by macroscopic polarization measurement based on a standard capacitive method. We have observed a strong increase of piezoelectric response under illumination, consistent with the previously reported giant photoinduced dielectric constant at low frequencies. We speculate that an intrinsic charge transfer photoinduced dipole in the perovskite cage may lie at the origin of this effect.

  5. Chirality Emergence in Thin Solid Films of Amino Acids by Polarized Light from Synchrotron Radiation and Free Electron Laser

    Directory of Open Access Journals (Sweden)

    Mashahiro Adachi

    2009-07-01

    Full Text Available One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of “chiral impulse” as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario. To experimentally introduce chiral structure into racemic films of amino acids (alanine, phenylalanine, isovaline, etc., we irradiated them with linearly polarized light (LPL from synchrotron radiation and circularly polarized light (CPL from a free electron laser. After the irradiation, we evaluated optical anisotropy by measuring the circular dichroism (CD spectra and verified that new Cotton peaks appeared at almost the same peak position as those of the corresponding non-racemic amino acid films. With LPL irradiation, two-dimensional anisotropic structure expressed as linear dichroism and/or linear birefringence was introduced into the racemic films. With CPL irradiation, the signs of the Cotton peaks exhibit symmetrical structure corresponding to the direction of CPL rotation. This indicates that some kinds of chiral structure were introduced into the racemic film. The CD spectra after CPL irradiation suggest the chiral structure should be derived from not only preferential photolysis but also from photolysis-induced molecular structural change. These results suggest that circularly polarized light sources in space could be associated with the origin of terrestrial homochirality; that is, they would be effective asymmetric exciting sources introducing chiral structures into bio-organic molecules or complex organic compounds.

  6. Phototaxis and polarotaxis hand in hand: night dispersal flight of aquatic insects distracted synergistically by light intensity and reflection polarization.

    Science.gov (United States)

    Boda, Pál; Horváth, Gábor; Kriska, György; Blahó, Miklós; Csabai, Zoltán

    2014-05-01

    Based on an earlier observation in the field, we hypothesized that light intensity and horizontally polarized reflected light may strongly influence the flight behaviour of night-active aquatic insects. We assumed that phototaxis and polarotaxis together have a more harmful effect on the dispersal flight of these insects than they would have separately. We tested this hypothesis in a multiple-choice field experiment using horizontal test surfaces laid on the ground. We offered simultaneously the following visual stimuli for aerial aquatic insects: (1) lamplit matte black canvas inducing phototaxis alone, (2) unlit shiny black plastic sheet eliciting polarotaxis alone, (3) lamplit shiny black plastic sheet inducing simultaneously phototaxis and polarotaxis, and (4) unlit matte black canvas as a visually unattractive control. The unlit matte black canvas trapped only a negligible number (13) of water insects. The sum (16,432) of the total numbers of water beetles and bugs captured on the lamplit matte black canvas (7,922) and the unlit shiny black plastic sheet (8,510) was much smaller than the total catch (29,682) caught on the lamplit shiny black plastic sheet. This provides experimental evidence for the synergistic interaction of phototaxis (elicited by the unpolarized direct lamplight) and polarotaxis (induced by the strongly and horizontally polarized plastic-reflected light) in the investigated aquatic insects. Thus, horizontally polarizing artificial lamplit surfaces can function as an effective ecological trap due to this synergism of optical cues, especially in the urban environment.

  7. Solving structure in the CP29 light harvesting complex with polarization-phased 2D electronic spectroscopy

    Science.gov (United States)

    Ginsberg, Naomi S.; Davis, Jeffrey A.; Ballottari, Matteo; Cheng, Yuan-Chung; Bassi, Roberto; Fleming, Graham R.

    2011-01-01

    The CP29 light harvesting complex from green plants is a pigment-protein complex believed to collect, conduct, and quench electronic excitation energy in photosynthesis. We have spectroscopically determined the relative angle between electronic transition dipole moments of its chlorophyll excitation energy transfer pairs in their local protein environments without relying on simulations or an X-ray crystal structure. To do so, we measure a basis set of polarized 2D electronic spectra and isolate their absorptive components on account of the tensor relation between the light polarization sequences used to obtain them. This broadly applicable advance further enhances the acuity of polarized 2D electronic spectroscopy and provides a general means to initiate or feed back on the structural modeling of electronically-coupled chromophores in condensed phase systems, tightening the inferred relations between the spatial and electronic landscapes of ultrafast energy flow. We also discuss the pigment composition of CP29 in the context of light harvesting, energy channeling, and photoprotection within photosystem II. PMID:21321222

  8. Chirality Emergence in Thin Solid Films of Amino Acids by Polarized Light from Synchrotron Radiation and Free Electron Laser

    Science.gov (United States)

    Takahashi, Jun-ichi; Shinojima, Hiroyuki; Seyama, Michiko; Ueno, Yuko; Kaneko, Takeo; Kobayashi, Kensei; Mita, Hajime; Adachi, Mashahiro; Hosaka, Masahito; Katoh, Masahiro

    2009-01-01

    One of the most attractive hypothesis for the origin of homochirality in terrestrial bioorganic compounds is that a kind of “chiral impulse” as an asymmetric excitation source induced asymmetric reactions on the surfaces of such materials such as meteorites or interstellar dusts prior to the existence of terrestrial life (Cosmic Scenario). To experimentally introduce chiral structure into racemic films of amino acids (alanine, phenylalanine, isovaline, etc.), we irradiated them with linearly polarized light (LPL) from synchrotron radiation and circularly polarized light (CPL) from a free electron laser. After the irradiation, we evaluated optical anisotropy by measuring the circular dichroism (CD) spectra and verified that new Cotton peaks appeared at almost the same peak position as those of the corresponding non-racemic amino acid films. With LPL irradiation, two-dimensional anisotropic structure expressed as linear dichroism and/or linear birefringence was introduced into the racemic films. With CPL irradiation, the signs of the Cotton peaks exhibit symmetrical structure corresponding to the direction of CPL rotation. This indicates that some kinds of chiral structure were introduced into the racemic film. The CD spectra after CPL irradiation suggest the chiral structure should be derived from not only preferential photolysis but also from photolysis-induced molecular structural change. These results suggest that circularly polarized light sources in space could be associated with the origin of terrestrial homochirality; that is, they would be effective asymmetric exciting sources introducing chiral structures into bio-organic molecules or complex organic compounds. PMID:19742124

  9. Quantitative analysis with advanced compensated polarized light microscopy on wavelength dependence of linear birefringence of single crystals causing arthritis

    Science.gov (United States)

    Takanabe, Akifumi; Tanaka, Masahito; Taniguchi, Atsuo; Yamanaka, Hisashi; Asahi, Toru

    2014-07-01

    To improve our ability to identify single crystals causing arthritis, we have developed a practical measurement system of polarized light microscopy called advanced compensated polarized light microscopy (A-CPLM). The A-CPLM system is constructed by employing a conventional phase retardation plate, an optical fibre and a charge-coupled device spectrometer in a polarized light microscope. We applied the A-CPLM system to measure linear birefringence (LB) in the visible region, which is an optical anisotropic property, for tiny single crystals causing arthritis, i.e. monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD). The A-CPLM system performance was evaluated by comparing the obtained experimental data using the A-CPLM system with (i) literature data for a standard sample, MgF2, and (ii) experimental data obtained using an established optical method, high-accuracy universal polarimeter, for the MSUM. The A-CPLM system was found to be applicable for measuring the LB spectra of the single crystals of MSUM and CPPD, which cause arthritis, in the visible regions. We quantitatively reveal the large difference in LB between MSUM and CPPD crystals. These results demonstrate the usefulness of the A-CPLM system for distinguishing the crystals causing arthritis.

  10. Treatment of Carpal Tunnel Syndrome in pregnancy with Polarized Polychromatic Non-coherent Light (Bioptron Light): A Preliminary, Prospective, Open Clinical Trial.

    Science.gov (United States)

    Dimitrios, Stasinopoulos; Stasinopoulos, Loannis

    2017-12-31

    The aim of this trial was to assess the efficacy of polarized polychromatic noncoherent light (Bioptron light) in the treatment of Carpal Tunnel Syndrome (CTS) in pregnancy. An uncontrolled experimental study was conducted in pregnant patients with CTS who visited our clinic from January 2006 to January 2010. Bioptron light (480-3400 nm; 95% polarization; 40 mW/cm 2 ; and 2.4 J/cm 2 ) was administered perpendicular to the carpal tunnel area. The irradiation time for each session was 6 min at an operating distance of 5-10 cm from the carpal tunnel area, twice each day, five days per week for 2 weeks. Pain and paraesthesia using a visual analogue scale (VAS) and finger pinch strength were evaluated at the end of treatment (week 2) and 1-month (week 6) after the end of treatment. The Student'sttest was used and p values Bioptron light is a reliable, safe, and effective treatment option in pregnant patients with CTS. Controlled clinical trials are needed to establish the absolute and relative effectiveness of this intervention.

  11. Polarized light (λ400-2000 nm) on third-degree burns in diabetic rats: immunohistochemical study.

    Science.gov (United States)

    Oliveira, Priscila Chagas; Pinheiro, Antônio Luiz Barbosa; Reis Junior, João Alves; de Castro, Isabelle C V; Gurgel, Clarissa; Noia, Manuela Pimentel; Meireles, Gyselle C S; Cangussu, Maria Cristina; Ramalho, Luciana Maria Pedreira

    2010-10-01

    The aim of this study was to evaluate with light microscopy the healing process of third-degree burns on diabetic rats treated with polarized light (λ400-2000 nm, 20 or 40 J/cm(2)/session, 40 mW/cm(2), 2.4 J/cm(2)/min, 5.5-cm beam diameter). Uncontrolled diabetes mellitus causes severe disruption of the body's metabolism, including healing. Polarized light sources have been shown to be effective in improving healing in many situations. Diabetes mellitus was induced with streptozotocin (60 mg/kg) in 45 male Wistar albino rats, and a third-degree burn (1.5 by 1.5 cm) was created on the dorsum of each animal under general anesthesia. The animals were randomly distributed into three groups: control, 20 J/cm(2), and 40 J/cm(2). Each group was then divided into three subgroups based on time of death (7, 14, 21 d). Phototherapy (20 or 40 J/cm(2) per session) was carried out immediately after the burning and repeated daily until the day before death. Following animal death, specimens were removed, embedded in paraffin, sectioned, and stained with hematoxylin and eosin (HE) or Sirius Red or immunomarked with CK AE1/AE3 antibody. Qualitative and semiquantitative analyses were performed under light microscopy. The results were statistically analyzed. The animals treated with 20 J/cm(2) showed significant differences with regard to revascularization and re-epithelialization. Although the 40 J/cm(2) group showed stimulation of fibroblastic proliferation as an isolated feature, no other difference from the control was observed. Our results suggest that the use of polarized light at 20 J/cm(2) effectively improves the healing of third-degree burns on diabetic animals at both early and late stages of repair.

  12. Asymmetric bistable reflection and polarization switching in a magnetic nonlinear multilayer structure

    DEFF Research Database (Denmark)

    Tuz, Vladimir R.; Novitsky, Denis V.; Prosvirnin, Sergey L.

    2014-01-01

    , while light reflected from the other side has its polarization unchanged. Using the nonlinear transfer matrix calculations in the frequency domain, it is demonstrated that defect resonances in the nonlinear reflection spectra undergo bending, resulting in polarization bistability of reflected light....... This bistability is shown to result in abrupt switching between linear polarization of the output reflected light when the input intensity is varied. This switching is confirmed in finite-difference time-domain simulations, and its hysteresis character is established....

  13. Mutual conversion and asymmetric transmission of linearly polarized light in bilayered chiral metamaterial.

    Science.gov (United States)

    Xu, Yiqun; Shi, Quanchao; Zhu, Zheng; Shi, Jinhui

    2014-10-20

    We propose a kind of planar chiral optical metamaterial consisting of two layers of connected I-shape resonators arranged by a twist angle of 90°. Numerical simulation results demonstrate that our scheme can realize a mutual polarization conversion and dual-band asymmetric transmission for linearly polarized waves in the optical regime. For the forward propagation, the x-to-y and y-to-x polarization conversions in the proposed bilayered metamaterial result from the concentric and eccentric C-shaped dimers, respectively. The current distributions of bilayered metamaterials at the resonant frequencies are presented to interpret the dual-band asymmetric transmission. The polarization conversion efficiency and resonant frequencies can be modified via parametric study.

  14. Influence of light polarization on the dynamics of optically pumped lasers

    Energy Technology Data Exchange (ETDEWEB)

    Arjona, M.; Corbalan, R. (Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)); Laguarta, F.; Pujol, J. (Departament d' Optica i Optometria, Universitat Politecnica de Catalunya, 08222 Terrassa (Spain)); Vilaseca, R. (Departament I. D' Optica, Universitat de Valencia, 46100 Burjassot (Spain))

    1990-06-01

    The dynamic behavior of a coherently pumped ring laser with a homogeneously broadened four-level medium is analyzed theoretically, considering linearly polarized pump and generated laser beams. The laser is shown to be much more stable when these polarizations are parallel than when they are orthogonal. In the latter case the instability pump threshold can be as low as four times the first laser threshold, and the laser dynamics shows Lorenz-type features.

  15. Light

    CERN Document Server

    Robertson, William C

    2003-01-01

    Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...

  16. Tailoring of polarization in electron blocking layer for electron confinement and hole injection in ultraviolet light-emitting diodes

    International Nuclear Information System (INIS)

    Lu, Yu-Hsuan; Pilkuhn, Manfred H.; Fu, Yi-Keng; Chu, Mu-Tao; Huang, Shyh-Jer; Su, Yan-Kuin; Wang, Kang L.

    2014-01-01

    The influence of the AlGaN electron blocking layer (EBL) with graded aluminum composition on electron confinement and hole injection in AlGaN-based ultraviolet light-emitting diodes (LEDs) are investigated. The light output power of LED with graded AlGaN EBL was markedly improved, comparing to LED with conventional EBL. In experimental results, a high increment of 86.7% can be obtained in light output power. Simulation analysis shows that via proper modification of the barrier profile from the last barrier of the active region to EBL, not only the elimination of electron overflow to p-type layer can be achieved but also the hole injection into the active region can be enhanced, compared to a conventional LED structure. The dominant factor to the performance improvement is shown to be the modulation of polarization field by the graded Al composition in EBL

  17. Tailoring of polarization in electron blocking layer for electron confinement and hole injection in ultraviolet light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yu-Hsuan; Pilkuhn, Manfred H. [Department of Electrical Engineering, Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Fu, Yi-Keng; Chu, Mu-Tao [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu 31040, Taiwan (China); Huang, Shyh-Jer, E-mail: yksu@mail.ncku.edu.tw, E-mail: totaljer48@gmail.com [Department of Electrical Engineering, Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095 (United States); Su, Yan-Kuin, E-mail: yksu@mail.ncku.edu.tw, E-mail: totaljer48@gmail.com [Department of Electrical Engineering, Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan (China); Department of Electronic Engineering, Kun-Shan University, Tainan 71003, Taiwan (China); Wang, Kang L. [Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095 (United States)

    2014-03-21

    The influence of the AlGaN electron blocking layer (EBL) with graded aluminum composition on electron confinement and hole injection in AlGaN-based ultraviolet light-emitting diodes (LEDs) are investigated. The light output power of LED with graded AlGaN EBL was markedly improved, comparing to LED with conventional EBL. In experimental results, a high increment of 86.7% can be obtained in light output power. Simulation analysis shows that via proper modification of the barrier profile from the last barrier of the active region to EBL, not only the elimination of electron overflow to p-type layer can be achieved but also the hole injection into the active region can be enhanced, compared to a conventional LED structure. The dominant factor to the performance improvement is shown to be the modulation of polarization field by the graded Al composition in EBL.

  18. Spatial light modulators for full cross-connections in optical networks

    Science.gov (United States)

    Juday, Richard D. (Inventor)

    2004-01-01

    A polarization-independent optical switch is disclosed for switching at least one incoming beam from at least one input source to at least one output drain. The switch includes a polarizing beam splitter to split each of the at least one incoming beam into a first input beam and a second input beam, wherein the first input beam and the second input beams are independently polarized; a wave plate optically coupled to the second input beam for converting the polarization of the second input beam to an appropriately polarized second input beam; a beam combiner optically coupled to the first input beam and the modified second input beam, wherein the beam combiner accepts the first input beam and the modified second input beam to produce a combined beam; the combined beam is invariant to the polarization state of the input source's polarization; and a controllable spatial light modulator optically coupled to the combined beam, wherein the combined beam is diffracted by the controllable spatial light modulator to place light at a plurality of output locations.

  19. Circular Polarization of Light By Planet Mercury and Enantiomorphism of Its Surface Minerals

    Science.gov (United States)

    Meierhenrich, U. J.; Thiemann, W. H.-P.; Barbier, B.; Brack, A.; Nahon, L.; Alcaraz, C.; Wolstencroft, R.

    Different mechanisms for the generation of circular polarization on the surface of planets and satellites are described. The observed values for Venus, the Moon, Mars, and Jupiter obtained by photo-polarimetric measurements with Earth based telescopes, showed accordance with theory. However, for planet Mercury asymmetric parameters in the circular polarization were measured that do not fit with calculations. For Bepi- Colombo, we propose to investigate this phenomenon using a concept which includes two instruments. The first instrument is a high-resolution optical polarimeter,[1,2] ca- pable to determine and map the circular polarization by remote scanning of Mercury's surface from the Mercury Planetary Orbiter MPO. The second instrument is an in situ sensor for the detection of the enantiomorphism of surface crystals and minerals, proposed to be included in the Mercury Lander MSE. [1] C. Alcaraz, R. Thissen, M. Compin, A. Jolly, M. Drescher, L. Nahon: First po- larization measurements of Ophelie: a versatile polarization VUV undulator at Super- Aco. SPIE 3773 (1999), 250-261. [2] C. Alcaraz, J.L. Marlats, D. Nether, B. Pilette, L. Nahon: A dedicated precise polarimeter for measurement of VUV versatile photon polarizations, Applied Optics, manuscript under preparation.

  20. submitter Phase transition observations and discrimination of small cloud particles by light polarization in expansion chamber experiments

    CERN Document Server

    Nichman, Leonid; Järvinen, Emma; Ignatius, Karoliina; Höppel, Niko Florian; Dias, Antonio; Heinritzi, Martin; Simon, Mario; Tröstl, Jasmin; Wagner, Andrea Christine; Wagner, Robert; Williamson, Christina; Yan, Chao; Connolly, Paul James; Dorsey, James Robert; Duplissy, Jonathan; Ehrhart, Sebastian; Frege, Carla; Gordon, Hamish; Hoyle, Christopher Robert; Kristensen, Thomas Bjerring; Steiner, Gerhard; McPherson Donahue, Neil; Flagan, Richard; Gallagher, Martin William; Kirkby, Jasper; Möhler, Ottmar; Saathoff, Harald; Schnaiter, Martin; Stratmann, Frank; Tomé, António

    2016-01-01

    Cloud microphysical processes involving the ice phase in tropospheric clouds are among the major uncertainties in cloud formation, weather, and general circulation models. The detection of aerosol particles, liquid droplets, and ice crystals, especially in the small cloud particle-size range below 50 μm, remains challenging in mixed phase, often unstable environments. The Cloud Aerosol Spectrometer with Polarization (CASPOL) is an airborne instrument that has the ability to detect such small cloud particles and measure the variability in polarization state of their backscattered light. Here we operate the versatile Cosmics Leaving OUtdoor Droplets (CLOUD) chamber facility at the European Organization for Nuclear Research (CERN) to produce controlled mixed phase and other clouds by adiabatic expansions in an ultraclean environment, and use the CASPOL to discriminate between different aerosols, water, and ice particles. In this paper, optical property measurements of mixed-phase clouds and viscous secondary ...

  1. Analysis of the effect of polarization traps and shallow impurities on the interlevel light absorption of quantum dots

    Directory of Open Access Journals (Sweden)

    V.I. Boichuk

    2017-12-01

    Full Text Available A spherical quantum dot (QD heterosystem CdS/SiO2 has been studied. Each QD has a hydrogen-like impurity in its center. Besides that, it has been accounted that a polarization trap for electron exists at the interfaces due to the difference between the QD and matrix dielectric permittivity. It has been defined that for small QD radii there are surface electron states. For different radii, partial contributions of the surface states into the electron energy caused by the electron-ion and electron-polarization charges interaction have been defined. The linear light absorption coefficient of noninteracting QDs has been calculated taking into account the QD dispersion by the size. It is shown that the surface states can be observed into different ranges of an electromagnetic spectrum.

  2. Localized enhancement of electric field in tip-enhanced Raman spectroscopy using radially and linearly polarized light.

    Science.gov (United States)

    Kazemi-Zanjani, Nastaran; Vedraine, Sylvain; Lagugné-Labarthet, François

    2013-10-21

    Finite-Difference Time-Domain (FDTD) calculations are used to characterize the electric field in the vicinity of a sharp silver or gold cone with an apex diameter of 10 nm. The simulations are utilized to predict the intensity and the distribution of the locally enhanced electric field in tip-enhanced Raman spectroscopy (TERS). A side-by-side comparison of the enhanced electric field induced by a radially and a linearly polarized light in both gap-mode and conventional TERS setup is performed. For this purpose, a radially polarized source is introduced and integrated into the FDTD modeling. Additionally, the optical effect of a thin protective layer of alumina on the enhancement of the electric field is investigated.

  3. Effects of electric field and light polarization on the electromagnetically induced transparency in an impurity doped quantum ring

    Science.gov (United States)

    Bejan, D.; Stan, C.; Niculescu, E. C.

    2018-01-01

    We theoretically investigated the effects of the impurity position, in-plane electric field, intensity and polarization of the probe and control lasers on the electromagnetically induced transparency (EIT) in GaAs/GaAlAs disc shaped quantum ring. Our study reveals that, depending on the impurity position, the quantum system presents two specific configurations for the EIT occurrence even in the absence of the external electric field, i.e. ladder-configuration or V-configuration, and changes the configuration from ladder to V for specific electric field values. The polarization of the probe and control lasers plays a crucial role in obtaining a good transparency. The electric field controls the red-shift (blue-shift) of the transparency window and modifies its width. The system exhibits birefringence for the probe light in a limited interval of electric field values.

  4. Circular polarization of light by planet Mercury and enantiomorphism of its surface minerals.

    Science.gov (United States)

    Meierhenrich, Uwe J; Thiemann, Wolfram H P; Barbier, Bernard; Brack, André; Alcaraz, Christian; Nahon, Laurent; Wolstencroft, Ray

    2002-04-01

    Different mechanisms for the generation of circular polarization by the surface of planets and satellites are described. The observed values for Venus, the Moon, Mars, and Jupiter obtained by photo-polarimetric measurements with Earth based telescopes, showed accordance with theory. However, for planet Mercury asymmetric parameters in the circular polarization were measured that do not fit with calculations. For BepiColombo, the ESA cornerstone mission 5 to Mercury, we propose to investigate this phenomenon using a concept which includes two instruments. The first instrument is a high-resolution optical polarimeter, capable to determine and map the circular polarization by remote scanning of Mercury's surface from the Mercury Planetary Orbiter MPO. The second instrument is an in situ sensor for the detection of the enantiomorphism of surface crystals and minerals, proposed to be included in the Mercury Lander MSE.

  5. Living Cells and Dynamic Molecules Observed with the Polarized Light Microscope: the Legacy of Shinya Inoué.

    Science.gov (United States)

    Tani, Tomomi; Shribak, Michael; Oldenbourg, Rudolf

    2016-08-01

    In 1948, Shinya Inoué arrived in the United States for graduate studies at Princeton. A year later he came to Woods Hole, starting a long tradition of summer research at the Marine Biological Laboratory (MBL), which quickly became Inoué's scientific home. Primed by his Japanese mentor, Katsuma Dan, Inoué followed Dan's mantra to work with healthy, living cells, on a fundamental problem (mitosis), with a unique tool set that he refined for precise and quantitative observations (polarized light microscopy), and a fresh and brilliant mind that was unafraid of challenging current dogma. Building on this potent combination, Inoué contributed landmark observations and concepts in cell biology, including the notion that there are dynamic, fine structures inside living cells, in which molecular assemblies such as mitotic spindle fibers exist in delicate equilibrium with their molecular building blocks suspended in the cytoplasm. In the late 1970s and 1980s, Inoué and others at the MBL were instrumental in conceiving video microscopy, a groundbreaking technique which married light microscopy and electronic imaging, ushering in a revolution in how we know and what we know about living cells and the molecular mechanisms of life. Here, we recount some of Inoué's accomplishments and describe how his legacy has shaped current activities in polarized light imaging at the MBL. © 2016 Marine Biological Laboratory.

  6. Forest-stream linkages: effects of terrestrial invertebrate input and light on diet and growth of brown trout (Salmo trutta in a boreal forest stream.

    Directory of Open Access Journals (Sweden)

    Tibor Erős

    Full Text Available Subsidies of energy and material from the riparian zone have large impacts on recipient stream habitats. Human-induced changes, such as deforestation, may profoundly affect these pathways. However, the strength of individual factors on stream ecosystems is poorly understood since the factors involved often interact in complex ways. We isolated two of these factors, manipulating the flux of terrestrial input and the intensity of light in a 2×2 factorial design, where we followed the growth and diet of two size-classes of brown trout (Salmo trutta and the development of periphyton, grazer macroinvertebrates, terrestrial invertebrate inputs, and drift in twelve 20 m long enclosed stream reaches in a five-month-long experiment in a boreal coniferous forest stream. We found that light intensity, which was artificially increased 2.5 times above ambient levels, had an effect on grazer density, but no detectable effect on chlorophyll a biomass. We also found a seasonal effect on the amount of drift and that the reduction of terrestrial prey input, accomplished by covering enclosures with transparent plastic, had a negative impact on the amount of terrestrial invertebrates in the drift. Further, trout growth was strongly seasonal and followed the same pattern as drift biomass, and the reduction of terrestrial prey input had a negative effect on trout growth. Diet analysis was consistent with growth differences, showing that trout in open enclosures consumed relatively more terrestrial prey in summer than trout living in covered enclosures. We also predicted ontogenetic differences in the diet and growth of old and young trout, where we expected old fish to be more affected by the terrestrial prey reduction, but we found little evidence of ontogenetic differences. Overall, our results showed that reduced terrestrial prey inputs, as would be expected from forest harvesting, shaped differences in the growth and diet of the top predator, brown trout.

  7. Polarized light microscopy-detectable structures of human oocytes and embryos are related to the likelihood of conception in IVF.

    Science.gov (United States)

    Molinari, Emanuela; Evangelista, Francesca; Racca, Cinzia; Cagnazzo, Celeste; Revelli, Alberto

    2012-10-01

    To clarify if birefringent structures of human oocytes and embryos, measurable by polarized light microscopy, have any value in predicting the chance of pregnancy in human in vitro fertilization and may halp to identify the most competent oocytes and embryos. The inner layer of the zona pellucida (IL-ZP) and the meiotic spindle (MS) were analyzed by polarized light microscopy in 258 oocytes and in the 209 embryos deriving from them. Data obtained from 102 ICSI cycles with conception were compared with those obtained in 156 cycles without conception. The retardance and area of the IL-ZP, as well as the retardance, length of the major axis, and area of the MS were measured. Furthermore, polarized light microscopy parameters were related to the embryo morphological score by multiple regression analysis. The mean area of the IL-ZP of both oocytes and embryos was significantly lower in conception than in non-conception cycles (p = 0.0001 for oocytes and p = 0.002 for embryos). The area of the IL-ZP in embryos was significantly, inversely related to the embryo morphological score (p = 0.011). The area, the major axis length and the retarcance of the MS, as well as the retardance of the IL-ZP in oocytes and embryos were comparable in conception and non-conception cycles. The area of the IL-ZP of the human oocytes may represent a marker of oocyte competence, as oocytes with a low IL-ZP area are more frequently obtained in conception cycles. When measured in embryos, a low IL-ZP area identifies embryos with a high chance of implantation.

  8. Influence of polar solvents on the enhancement of light-ends in ...

    African Journals Online (AJOL)

    Crude oil 'micelle' can be dispersed into fuels, oil and resin/asphalthene components using some hydrocarbon solvents. This can be adapted towards influencing/enhancing its product slates during the processing of crude oils. This research was carried out to investigate the effect of polar solvents (ethanol and acetone) in ...

  9. Moving systems of polar dimeric capsules out of thermal equilibrium by light irradiation.

    Science.gov (United States)

    Díaz-Moscoso, Alejandro; Arroyave, Frank A; Ballester, Pablo

    2016-02-18

    Heterodimeric capsules self-assembled from tetraurea calix[4]pyrrole and tetraurea calix[4]arene provide unique molecular containers for the organised inclusion of small polar molecules. By inserting stimuli-responsive groups (azobenzene) in the heterocapsule structure, we are able to modify the equilibrium state of the system or the exchange between different host-guest assemblies in a reversible manner.

  10. Polarization optics for out-of-plane light trajectories: GRIN lenses and optical fibers

    Science.gov (United States)

    Tentori, Diana; Trevino-Martinez, Fernando; Ayala-Diaz, Cesar; Camacho, Javier; Mendieta-Jimenez, Francisco J.

    2001-08-01

    The volution of the state of polarization along an out-of- plane trajectory has been widely studied for monomode optical fibers. To demonstrate the validity of our proposal we compare the results predicted by our model with experimental result obtained for helically wound optical fibers and the conoscopic patterns obtained for GRIN lenses when oblique illumination is used.

  11. Shadows and cavities in protoplanetary disks: HD 163296, HD 141569A, and HD 150193A in polarized light

    Science.gov (United States)

    Garufi, A.; Quanz, S. P.; Schmid, H. M.; Avenhaus, H.; Buenzli, E.; Wolf, S.

    2014-08-01

    Context. The morphological evolution of dusty disks around young (a few Myr old) stars is pivotal for a better understanding of planet formation. Since both dust grains and the global disk geometry evolve on short timescales, high-resolution imaging of a sample of objects may provide important indications about this evolution. Aims: We enlarge the sample of protoplanetary disks imaged in polarized light with high-resolution imaging (≲0.2″) by observing the Herbig Ae/Be stars HD 163296, HD 141569A, and HD 150193A. We combine our data with previous datasets to understand the larger context of their morphology. Methods: Polarimetric differential imaging is an attractive technique with which to image at near-IR wavelengths a significant fraction of the light scattered by the circumstellar material. The unpolarized stellar light is canceled out by combining two simultaneous orthogonal polarization states. This allowed us to achieve an inner working angle and an angular resolution as low as ~0.1″. Results: We report a weak detection of the disk around HD 163296 in the H and KS bands. The disk is resolved as a broken ring structure with a significant surface brightness drop inward of 0.6″. No sign of extended polarized emission is detected from the disk around HD 141569A and HD 150193A. Conclusions: We propose that the absence of scattered light in the inner 0.6″ around HD 163296 and the non-detection of the disk around HD 150193A may be due to similar geometric factors. Since these disks are known to be flat or only moderately flared, self-shadowing by the disk inner wall is the favored explanation. We show that the polarized brightness of a number of disks is indeed related to their flaring angle. Other scenarios (such as dust grain growth or interaction with icy molecules) are also discussed. On the other hand, the non-detection of HD 141569A is consistent with previous datasets that revealed a huge cavity in the dusty disk. Based on observations collected at

  12. Unexpected attraction of polarotactic water-leaving insects to matt black car surfaces: mattness of paintwork cannot eliminate the polarized light pollution of black cars.

    Directory of Open Access Journals (Sweden)

    Miklos Blaho

    Full Text Available The horizontally polarizing surface parts of shiny black cars (the reflection-polarization characteristics of which are similar to those of water surfaces attract water-leaving polarotactic insects. Thus, shiny black cars are typical sources of polarized light pollution endangering water-leaving insects. A new fashion fad is to make car-bodies matt black or grey. Since rough (matt surfaces depolarize the reflected light, one of the ways of reducing polarized light pollution is to make matt the concerned surface. Consequently, matt black/grey cars may not induce polarized light pollution, which would be an advantageous feature for environmental protection. To test this idea, we performed field experiments with horizontal shiny and matt black car-body surfaces laid on the ground. Using imaging polarimetry, in multiple-choice field experiments we investigated the attractiveness of these test surfaces to various water-leaving polarotactic insects and obtained the following results: (i The attractiveness of black car-bodies to polarotactic insects depends in complex manner on the surface roughness (shiny, matt and species (mayflies, dolichopodids, tabanids. (ii Non-expectedly, the matt dark grey car finish is much more attractive to mayflies (being endangered and protected in many countries than matt black finish. (iii The polarized light pollution of shiny black cars usually cannot be reduced with the use of matt painting. On the basis of these, our two novel findings are that (a matt car-paints are highly polarization reflecting, and (b these matt paints are not suitable to repel polarotactic insects. Hence, the recent technology used to make matt the car-bodies cannot eliminate or even can enhance the attractiveness of black/grey cars to water-leaving insects. Thus, changing shiny black car painting to matt one is a disadvantageous fashion fad concerning the reduction of polarized light pollution of black vehicles.

  13. Unexpected attraction of polarotactic water-leaving insects to matt black car surfaces: mattness of paintwork cannot eliminate the polarized light pollution of black cars.

    Science.gov (United States)

    Blaho, Miklos; Herczeg, Tamas; Kriska, Gyorgy; Egri, Adam; Szaz, Denes; Farkas, Alexandra; Tarjanyi, Nikolett; Czinke, Laszlo; Barta, Andras; Horvath, Gabor

    2014-01-01

    The horizontally polarizing surface parts of shiny black cars (the reflection-polarization characteristics of which are similar to those of water surfaces) attract water-leaving polarotactic insects. Thus, shiny black cars are typical sources of polarized light pollution endangering water-leaving insects. A new fashion fad is to make car-bodies matt black or grey. Since rough (matt) surfaces depolarize the reflected light, one of the ways of reducing polarized light pollution is to make matt the concerned surface. Consequently, matt black/grey cars may not induce polarized light pollution, which would be an advantageous feature for environmental protection. To test this idea, we performed field experiments with horizontal shiny and matt black car-body surfaces laid on the ground. Using imaging polarimetry, in multiple-choice field experiments we investigated the attractiveness of these test surfaces to various water-leaving polarotactic insects and obtained the following results: (i) The attractiveness of black car-bodies to polarotactic insects depends in complex manner on the surface roughness (shiny, matt) and species (mayflies, dolichopodids, tabanids). (ii) Non-expectedly, the matt dark grey car finish is much more attractive to mayflies (being endangered and protected in many countries) than matt black finish. (iii) The polarized light pollution of shiny black cars usually cannot be reduced with the use of matt painting. On the basis of these, our two novel findings are that (a) matt car-paints are highly polarization reflecting, and (b) these matt paints are not suitable to repel polarotactic insects. Hence, the recent technology used to make matt the car-bodies cannot eliminate or even can enhance the attractiveness of black/grey cars to water-leaving insects. Thus, changing shiny black car painting to matt one is a disadvantageous fashion fad concerning the reduction of polarized light pollution of black vehicles.

  14. Light polarization sensitive photodetectors with m- and r-plane homoepitaxial ZnO/ZnMgO quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Tabares, G.; Hierro, A., E-mail: adrian.hierro@upm.es; Lopez-Ponce, M.; Muñoz, E. [ISOM and Dpto. Ingeniería Electrónica, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Vinter, B.; Chauveau, J.-M. [CRHEA-CNRS, Av. B. Gregory, 06560 Valbonne (France); University of Nice Sophia Antipolis, Parc Valrose, 06102 Nice cedex 2 (France)

    2015-02-09

    Homoepitaxial ZnO/(Zn,Mg)O multiple quantum wells (MQWs) grown with m- and r-plane orientations are used to demonstrate Schottky photodiodes sensitive to the polarization state of light. In both orientations, the spectral photoresponse of the MQW photodiodes shows a sharp excitonic absorption edge at 3.48 eV with a very low Urbach tail, allowing the observation of the absorption from the A, B and C excitonic transitions. The absorption edge energy is shifted by ∼30 and ∼15 meV for the m- and r-plane MQW photodiodes, respectively, in full agreement with the calculated polarization of the A, B, and C excitonic transitions. The best figures of merit are obtained for the m-plane photodiodes, which present a quantum efficiency of ∼11%, and a specific detectivity D* of ∼6.4 × 10{sup 10} cm Hz{sup 1/2}/W. In these photodiodes, the absorption polarization sensitivity contrast between the two orthogonal in-plane axes yields a maximum value of (R{sub ⊥}/R{sub ||}){sub max} ∼ 9.9 with a narrow bandwidth of ∼33 meV.

  15. Electron-spin filter and polarizer in a standing light wave

    Science.gov (United States)

    Ahrens, Sven

    2017-11-01

    We demonstrate the theoretical feasibility of spin-dependent diffraction and spin polarization of an electron in two counterpropagating, circularly polarized laser beams. The spin dynamics appears in a two-photon process of the Kapitza-Dirac effect in the Bragg regime. We show the spin dependence of the diffraction process by comparison of the time evolution of spin-up and spin-down electrons in a relativistic quantum simulation. We further discuss the spin properties of the scattering by studying an analytically approximated solution of the time-evolution matrix. A classification scheme in terms of unitary or nonunitary propagation matrices is used for establishing a generalized and spin-independent description of the spin properties in the diffraction process.

  16. Forward scattering of polarized light from a turbid slab: theory and Monte Carlo simulations.

    Science.gov (United States)

    Otsuki, Soichi

    2016-12-20

    It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in turbid slab media. Monte Carlo simulations generate a reduced effective Mueller matrix for forward scattering, which satisfies reciprocity and mirror symmetry, but satisfies only reciprocity if the medium contains chiral components. The scattering matrix was factorized by using the Lu-Chipman polar decomposition, which affords the polarization parameters as a function of the radial distance from the center. The depolarization coefficients decrease with increasing distance, whereas the scattering-induced linear diattenuation and retardance become larger in the middle-distance range. The optical rotation for a chiral medium increases with increasing distance.

  17. Reflecting metallic metasurfaces designed with stochastic optimization as waveplates for manipulating light polarization

    Science.gov (United States)

    Haberko, Jakub; Wasylczyk, Piotr

    2018-03-01

    We demonstrate that a stochastic optimization algorithm with a properly chosen, weighted fitness function, following a global variation of parameters upon each step can be used to effectively design reflective polarizing optical elements. Two sub-wavelength metallic metasurfaces, corresponding to broadband half- and quarter-waveplates are demonstrated with simple structure topology, a uniform metallic coating and with the design suited for the currently available microfabrication techniques, such as ion milling or 3D printing.

  18. Periodic array of quantum rings strongly coupled to circularly polarized light as a topological insulator

    Science.gov (United States)

    Kozin, V. K.; Iorsh, I. V.; Kibis, O. V.; Shelykh, I. A.

    2018-01-01

    We demonstrate theoretically that a strong high-frequency circularly polarized electromagnetic field can turn a two-dimensional periodic array of interconnected quantum rings into a topological insulator. The elaborated approach is applicable to calculate and analyze the electron energy spectrum of the array, the energy spectrum of the edge states, and the corresponding electronic densities. As a result, the present theory paves the way to optical control of the topological phases in ring-based mesoscopic structures.

  19. On the role of strong gravity in polarization from scattering of light in relativistic flows

    Czech Academy of Sciences Publication Activity Database

    Horák, Jiří; Karas, Vladimír

    2006-01-01

    Roč. 365, č. 3 (2006), s. 813-826 ISSN 0035-8711 R&D Projects: GA MŠk(CZ) LC06014; GA AV ČR(CZ) IAA300030510; GA ČR GA205/03/0902 Institutional research plan: CEZ:AV0Z10030501 Keywords : polarization * black hole physics * relativity Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.057, year: 2006

  20. A portable liquid crystal-based polarized light system for the detection of organophosphorus nerve gas

    Science.gov (United States)

    He, Feng Jie; Liu, Hui Long; Chen, Long Cong; Xiong, Xing Liang

    2018-03-01

    Liquid crystal (LC)-based sensors have the advantageous properties of being fast, sensitive, and label-free, the results of which can be accessed directly only through the naked eye. However, the inherent disadvantages possessed by LC sensors, such as relying heavily on polarizing microscopes and the difficulty to quantify, have limited the possibility of field applications. Herein, we have addressed these issues by constructing a portable polarized detection system with constant temperature control. This system is mainly composed of four parts: the LC cell, the optics unit, the automatic temperature control unit, and the image processing unit. The LC cell was based on the ordering transitions of LCs in the presence of analytes. The optics unit based on the imaging principle of LCs was designed to substitute the polarizing microscope for the real-time observation. The image processing unit is expected to quantify the concentration of analytes. The results have shown that the presented system can detect dimethyl methyl phosphonate (a stimulant for organophosphorus nerve gas) within 25 s, and the limit of detection is about 10 ppb. In all, our portable system has potential in field applications.

  1. [A non-invasive glucose measurement method based on orthogonal twin-polarized light and its pilot experimental investigation].

    Science.gov (United States)

    Wang, Hong; Wu, Baoming; Liu, Ding

    2010-04-01

    In order to overcome the existing shortcomings of the non-invasive blood glucose polarized light measurement methods of optical heterodyne detection and direct detection, we present in this paper a new orthogonal twin-polarized light (OTPL) non-invasive blood glucose measurement method, which converts the micro-angle rotated by an optical active substance such as glucose to the energy difference of OTPL, amplifies the signals by the high-sensitivity lock-in amplifier made of relevant principle, controls Faraday coil current to compensate the changes in deflection angle caused by blood glucose, and makes use of the linear relationship between blood glucose concentration and Faraday coil current to calculate blood glucose concentration. In our comparative experiment using the data measured by LX-20 automatic biochemical analyzer as a standard, a 0.9777 correlation coefficient is obtained in glucose concentration experiment, and a 0.952 in serum experiment. The result shows that this method has higher detection sensitivity and accuracy and lays a foundation for the development of practical new type of non-invasive blood glucose tester for diabetic patients.

  2. Bichromatic coherent random lasing from dye-doped polymer stabilized blue phase liquid crystals controlled by pump light polarization

    Science.gov (United States)

    Wang, Lei; Wang, Meng; Yang, Mingchao; Shi, Li-Jie; Deng, Luogen; Yang, Huai

    2016-09-01

    In this paper, we investigate the bichromatic coherent random lasing actions from the dye-doped polymer stabilized blue phase liquid crystals. Two groups of lasing peaks, of which the full widith at half maximum is about 0.3 nm, are clearly observed. The shorter- and longer-wavelength modes are associated with the excitation of the single laser dye (DCM) monomers and dimers respectively. The experimental results show that the competition between the two groups of the lasing peaks can be controlled by varying the polarization of the pump light. When the polarization of the pump light is rotated from 0° to 90°, the intensity of the shorter-wavelength lasing peak group reduces while the intensity of the longer-wavelength lasing peak group increases. In addition, a red shift of the longer-wavelength modes is also observed and the physical mechanisms behind the red-shift phenomenon are discussed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474021 and 51333001), the Key Program for International S&T Cooperation Projects of China (Grant No. 2013DFB50340), the Issues of Priority Development Areas of the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120001130005), and the Key (Key Grant) Project of Chinese Ministry of Education (Grant No. 313002).

  3. An optical investigation of dentinal discoloration due to commonly endodontic sealers, using the transmitted light polarizing microscopy and spectrophotometry.

    Science.gov (United States)

    Suciu, Ioana; Ionescu, Ecaterina; Dimitriu, Bogdan Alexandru; Bartok, Ruxandra Ioana; Moldoveanu, Georgiana Florentina; Gheorghiu, Irina Maria; Suciu, Ileana; Ciocîrdel, Mihai

    2016-01-01

    The aim of this study was to establish the degree of tooth crown staining by commonly used endodontic sealers. Crown discolorations by tooth canal sealers [AH Plus (Dentsply DeTrey Gmbh, Konstanz, Germany); Endofill (Produits Dentaires SA, Vevey, Switzerland); Apexit (Dentsply DeTrey Gmbh, Konstanz, Germany); and MTA Fillapex (Angelus, Londrina, Brazil)] were tested on extracted human premolars. The samples were divided into five groups of five samples each, after root canal sealing. Five teeth were used as control groups. The spectrophotometric method was performed in order to quantify in terms of color change of the coronal part (it was also recorded a track on how the color changes over time). For the microscopic study of the extracted dental specimens subjected to this study, polarized transmitted light microscopy was used. This method involves the development of special microscopic preparations, called "thin sections". In our case, the thin section was performed on 20 prepared and obturated recently extracted teeth. The degree of discoloration was determined after one week and three months using spectrophotometry and polarized light microscopy. All sealers usually cause some degree of discoloration on the cervical aspect of the crowns that increases in time. AH Plus and Endofill caused the greatest discoloration, followed by Apexit and MTA Fillapex.

  4. Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy.

    Science.gov (United States)

    Klatt, Judith M; Meyer, Steffi; Häusler, Stefan; Macalady, Jennifer L; de Beer, Dirk; Polerecky, Lubos

    2016-04-01

    We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (light conditions. In contrast, B/C mats formed at locations where oxygen in the water column was comparatively abundant (>45 μM) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater.

  5. 3D-surface reconstruction method for diffuse optical tomography phantoms and tissues using structured and polarized light

    Science.gov (United States)

    Baum, K.; Hartmann, R.; Bischoff, T.; Himmelreich, F.; Heverhagen, J. T.

    2011-07-01

    In recent years optical methods became increasingly popular for pre-clinical research and small animal imaging. One main field in biomedical optics research is the diffuse optical tomography (DOT). Many new systems were invented for small animal imaging and breast cancer detection. In combination with the progress in the development of optical markers, optical detectors and near infrared light sources, these new systems have become a formidable source of information. Most of the systems detect the transmitted light which passes through an object and one observes the intensity variations on the detector side. The biggest challenge for all diffuse optical tomography systems is the enormous scattering of light in tissues and tissue-like phantoms resulting in loss of image information. Many systems work with contact gels and optical fibers that have direct contact with the object to neglect the light path between surface and detector. Highly developed mathematic models and reconstruction algorithms based on FEM and Monte Carlo simulations describe the light transport inside tissues and determine differences in absorption and scattering coefficients inside. The proposed method allows a more exact description of the orientation of surface elements from semi-transparent objects towards the detector. Using Polarization Difference Imaging (PDI) in combination with structured light 3D-scanning, it is possible to separate information from the surface from that of the subsurface. Thus, the actual surface shape can be determined. Furthermore, overlaying byproducts caused by inter-reflections and multiple scattering can be filtered from the basic image information with this method. To enhance the image quality, the intensity dispersion between surface and camera is calculated and the creation of 3D-FEM-meshes simplified.

  6. Textile solar light collectors based on models for polar bear hair

    Energy Technology Data Exchange (ETDEWEB)

    Bahners, Thomas; Schlosser, Uwe; Schollmeyer, Eckhard [Deutsches Textilforschungszentrum Nord-West e.V., Adlerstr. 1, D-47798 Krefeld (Germany); Gutmann, Rainer [Institut fuer Textilchemie und Chemiefasern, Koerschtalstr. 26, D-73770 Denkendorf (Germany)

    2008-12-15

    Concepts of technical fibers following models for the polar bear hair to be used for textile solar collectors are discussed. The approach to coat fibers with a thin layer into which fluorescent dyestuff was dispersed was studied experimentally. Modified fibers made of different polymers were characterized with respect to optical properties relevant for the bionic model. In the case of poly(methylmethacrylate) fibers, the envisaged effect could be achieved to high efficiency. The optical performance could be enhanced by ultrasonic dispersion of the dyestuff in the coating matrix. The effect is less significant in semi-crystalline fibers such as poly(ethylene terephthalate), which is attributed to diffuse scattering. (author)

  7. Polarization-controlled luminaires utilizing multiple Fresnel reflections

    Science.gov (United States)

    Falicoff, Waqidi; Minano, Juan C.; Caulfield, H. John; Alvarez, Roberto

    2003-11-01

    A novel luminaire utilizes repeated Fresnel reflections by angled surfaces to transform a small collimated input beam into a controlled output pattern with a high degree of polarization, either linear or radial. Applications to backlighting, front-lighting, optical communications and automotive lighting will be discussed.

  8. THE ORIENTATION OF THE E-VECTOR OF LINEARLY POLARIZED LIGHT DOES NOT AFFECT THE BEHAVIOUR OF THE PIGEON COLUMBA LIVIA

    Science.gov (United States)

    Coemans; Hzn; Nuboer

    1994-06-01

    Orientation with reference to the time-compensated sun-azimuth compass has been established for the homing pigeon Columba livia. Previous qualitative studies claim that pigeons are sensitive to the orientation of a polarizer and it has been suggested that these animals are able to use sky-light polarization as an indirect reference to the sun's position when the latter is shielded from view. We report experiments which were undertaken to quantify the sensitivity of the homing pigeon to the orientation of linearly polarized light. The results of our initial experiments suggested that the animals responded to secondary cues. Further experiments were carried out to avoid such artefacts. Under circumstances where secondary cues were rigorously avoided, we were, however, not able to demonstrate any directional response that was caused by the E-vector orientation of the illumination. These results throw doubt on the suggested polarization-sensitivity of birds in general.

  9. Polarized light for horizontal incidence and reflection by plane-parallel atmospheres

    NARCIS (Netherlands)

    Hovenier, J.W.; Stam, D.M.

    2007-01-01

    We show that the intensity vector of light reflected by a plane-parallel atmosphere is discontinuous if the directions of incidence and reflection are both horizontal. An exact expression describing the discontinuity is presented. This expression shows that the discontinuity is only due to first

  10. influence of polar solvents on the enhancement of light-ends

    African Journals Online (AJOL)

    user

    Unfortunately, light crude oil reserve is fast depleting [1]. This is perhaps one of the ... reduced to a Crude Dispersion System (CDS), the smallest of it being referred to as .... Table 3: Comparison of the yields of fractional cuts obtained by TBP distillation crude and the various Ethanol blends. Fractional cut, 0C. Pure crude 0%.

  11. Light-directing omnidirectional circularly polarized reflection from liquid-crystal droplets.

    Science.gov (United States)

    Fan, Jing; Li, Yannian; Bisoyi, Hari Krishna; Zola, Rafael S; Yang, Deng-Ke; Bunning, Timothy J; Weitz, David A; Li, Quan

    2015-02-09

    Constructing and tuning self-organized three-dimensional (3D) superstructures with tailored functionality is crucial in the nanofabrication of smart molecular devices. Herein we fabricate a self-organized, phototunable 3D photonic superstructure from monodisperse droplets of one-dimensional cholesteric liquid crystal (CLC) containing a photosensitive chiral molecular switch with high helical twisting power. The droplets are obtained by a glass capillary microfluidic technique by dispersing into PVA solution that facilitates planar anchoring of the liquid-crystal molecules at the droplet surface, as confirmed by the observation of normal incidence selective circular polarized reflection in all directions from the core of individual droplet. Photoirradiation of the droplets furnishes dynamic reflection colors without thermal relaxation, whose wavelength can be tuned reversibly by variation of the irradiation time. The results provided clear evidence on the phototunable reflection in all directions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. GLE and Sub-GLE Redefinition in the Light of High-Altitude Polar Neutron Monitors

    Science.gov (United States)

    Poluianov, S. V.; Usoskin, I. G.; Mishev, A. L.; Shea, M. A.; Smart, D. F.

    2017-11-01

    The conventional definition of ground-level enhancement (GLE) events requires a detection of solar energetic particles (SEP) by at least two differently located neutron monitors. Some places are exceptionally well suitable for ground-based detection of SEP - high-elevation polar regions with negligible geomagnetic and reduced atmospheric energy/rigidity cutoffs. At present, there are two neutron-monitor stations in such locations on the Antarctic plateau: SOPO/SOPB (at Amundsen-Scott station, 2835 m elevation), and DOMC/DOMB (at Concordia station, 3233 m elevation). Since 2015, when the DOMC/DOMB station started continuous operation, a relatively weak SEP event that was not detected by sea-level neutron-monitor stations was registered by both SOPO/SOPB and DOMC/DOMB, and it was accordingly classified as a GLE. This would lead to a distortion of the homogeneity of the historic GLE list and the corresponding statistics. To address this issue, we propose to modify the GLE definition so that it maintains the homogeneity: A GLE event is registered when there are near-time coincident and statistically significant enhancements of the count rates of at least two differently located neutron monitors, including at least one neutron monitor near sea level and a corresponding enhancement in the proton flux measured by a space-borne instrument(s). Relatively weak SEP events registered only by high-altitude polar neutron monitors, but with no response from cosmic-ray stations at sea level, can be classified as sub-GLEs.

  13. Stereo photograph of atomic arrangement by circularly-polarized-light two-dimensional photoelectron spectroscopy

    CERN Document Server

    Daimon, H

    2003-01-01

    A stereo photograph of atomic arrangement was obtained for the first time. The stereo photograph was displayed directly on the screen of display-type spherical-mirror analyzer without any computer-aided conversion process. This stereo photography was realized taking advantage of the phenomenon of circular dichroism in photoelectron angular distribution due to the reversal of orbital angular momentum of photoelectrons. The azimuthal shifts of forward focusing peaks in a photoelectron angular distribution pattern taken with left and right helicity light in a special arrangement are the same as the parallaxes in a stereo view of atoms. Hence a stereoscopic recognition of three-dimensional atomic arrangement is possible, when the left eye and the right eye respectively view the two images obtained by left and right helicity light simultaneously.

  14. Photo double ionization of helium 100 eV and 450 eV above threshold: I. Linearly polarized light

    International Nuclear Information System (INIS)

    Knapp, A; Kheifets, A; Bray, I; Weber, Th; Landers, A L; Schoessler, S; Jahnke, T; Nickles, J; Kammer, S; Jagutzki, O; Schmidt, L Ph H; Schoeffler, M; Osipov, T; Prior, M H; Schmidt-Boecking, H; Cocke, C L; Doerner, R

    2005-01-01

    We present a joint experimental and theoretical study for the fully differential cross section of the photo double ionization (PDI) of helium with linearly polarized light at the excess energies E exc = 100 eV and 450 eV above the threshold. The fully differential cross section is obtained by measuring the three-dimensional momentum vectors of one electron and the He 2+ ion in coincidence using the COLTRIMS method. We give an overview of the momentum distribution of the three-body continuum 100 eV above the threshold. We show angular distributions for both electrons for various energy sharings at E exc = 100 eV and 450 eV. The experimental results are well reproduced by a set of convergent close-coupling (CCC) calculations

  15. Determining the molecular origin of radiation damage/enhancement in electro-optic polymeric materials through polarized light microscopy

    Science.gov (United States)

    Perez-Moreno, Javier

    2014-09-01

    Previous studies on the radiation effects upon polymer and polymer-based photonic materials suggest that the radiation resistance of the material is heavily dependent on the choice of polymer-host and guest-chromophore. The best results to date have been achieved with electro optic polymeric materials based on CLD1 doped in APC, which has resulted in improved performance at the device level upon gamma-ray irradiation at moderate doses. Still, our understanding of the physical mechanisms behind the enhancement of the performance is unclear. In this paper, we discuss how polarized light microscopy could be used as a means to quantify the effect of the different physical parameters that influence the optical response of electro-optic polymeric thin film samples.

  16. The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones

    Science.gov (United States)

    Cassar, N.; Difiore, P. J.; Barnett, B. A.; Bender, M. L.; Bowie, A. R.; Tilbrook, B.; Petrou, K.; Westwood, K. J.; Wright, S. W.; Lefevre, D.

    2011-02-01

    The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP) and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ) and the northern reaches of the Polar Frontal Zone (PFZ), we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense) study, which occurred in January-February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m-2 d-1. NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (export from the Southern Ocean mixed layer.

  17. Solid polymer films exhibiting handedness-switchable, full-color-tunable selective reflection of circularly polarized light.

    Science.gov (United States)

    Nagata, Yuuya; Takagi, Keisuke; Suginome, Michinori

    2014-07-16

    Poly(quinoxaline-2,3-diyl)s bearing (S)-2-methylbutyl, n-butyl, and 8-chlorooctyl groups as side chains were synthesized to fabricate dry solid polymer thin films. These films exhibited selective reflection of right-handed circular polarized light (CPL) in the visible region after annealing in CHCl3 vapor at room temperature. The handedness of reflected CPL was inverted to the left after annealing in 1,2-dichloroethane vapor. It was also found that the color of a particular single film along with the handedness of reflected CPL were fully tuned reversibly, upon exposure of the film to the vapor of various mixtures of chloroform and 1,2-dichloroethane in different ratios.

  18. Analysis of peripheral thermal damage after laser irradiation of dentin using polarized light microscopy and synchrotron radiation infrared spectromicroscopy

    Science.gov (United States)

    Dela Rosa, Alfredo; Sarma, Anupama V.; Le, Charles Q.; Jones, Robert S.; Fried, Daniel

    2004-05-01

    It is necessary to minimize peripheral thermal damage during laser irradiation, since thermal damage to collagen and mineral compromises the bond strength to restorative materials in dentin and inhibits healing and osteointegration in bone. The overall objective of this study was to test the hypothesis that lasers resonant to the specific absorption of water, collagen, and hydroxyapatite with pulse durations less than the thermal relaxation times at each respective laser wavelength will efficiently remove dentin with minimal peripheral thermal damage. Precise incisions were produced in 3 x 3 mm2 blocks of human dentin using CO2 (9.6 μm), Er:YSGG (2.79 μm), and Nd:YAG (355 nm) lasers with and without a computer controlled water spray. Polarization-sensitive optical coherence tomography was used to obtain optical cross-sections of each incision to determine the rate and efficiency of ablation. The peripheral thermal damage zone around each incision was analyzed using polarized light microscopy (PLM) and Synchrotron-Radiation Fourier Transform Infrared Spectro-microscopy (SR-FTIR). Thermally induced chemical changes to both mineral and the collagen matrix was observed with SR-FTIR with a 10-μm spatial resolution and those changes were correlated with optical changes observed with PLM. Minimal (alveolar bone.

  19. Defect-Resistant Radiative Performance of m-Plane Immiscible Al1-xInxN Epitaxial Nanostructures for Deep-Ultraviolet and Visible Polarized Light Emitters.

    Science.gov (United States)

    Chichibu, Shigefusa F; Kojima, Kazunobu; Uedono, Akira; Sato, Yoshitaka

    2017-02-01

    Planar vacuum-fluorescent-display devices emitting polarized UV-C, blue, and green light are demonstrated using immiscible Al 1- x In x N nanostructures grown in nonpolar m-directions. Despite the presence of high concentration of nonradiative recombination centers, the Al 1- x In x N nanostructures emit polarized light with the luminescence lifetimes of 22-32 ps at 300 K. This defect-resistant radiative performance suggests supernormal localized characteristics of electron-hole pairs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Mapping Circumstellar Matter with Polarized Light: The Case of Supernova 2014J in M82

    Science.gov (United States)

    Yang, Yi; Wang, Lifan; Baade, Dietrich; Brown, Peter. J.; Cikota, Aleksandar; Cracraft, Misty; Höflich, Peter A.; Maund, Justyn R.; Patat, Ferdinando; Sparks, William B.; Spyromilio, Jason; Stevance, Heloise F.; Wang, Xiaofeng; Wheeler, J. Craig

    2018-02-01

    Optical polarimetry is an effective way of probing the environment of a supernova for dust. We acquired linear HST ACS/WFC polarimetry in bands F475W, F606W, and F775W of the supernova (SN) 2014J in M82 at six epochs from ∼277 days to ∼1181 days after the B-band maximum. The polarization measured at day 277 shows conspicuous deviations from other epochs. These differences can be attributed to at least ∼{10}-6 {M}ȯ of circumstellar dust located at a distance of ∼ 5× {10}17 {cm} from the SN. The scattering dust grains revealed by these observations seem to be aligned with the dust in the interstellar medium that is responsible for the large reddening toward the supernova. The presence of this circumstellar dust sets strong constraints on the progenitor system that led to the explosion of SN 2014J; however, it cannot discriminate between single- and double-degenerate models.

  1. Variation in the circularly polarized light reflection of Lomaptera (Scarabaeidae) beetles.

    Science.gov (United States)

    Carter, I E; Weir, K; McCall, M W; Parker, A R

    2016-07-01

    An extended spectroscopic study on the left-through-left circularly polarized reflection spectra of a large number of beetles from the Australasian Scrabaeidae:Cetoniinae of the Lomaptera genus was undertaken. We have obtained a five-category spectral classification. The principal spectral features, which even within the genus range from blue to infrared, are related to structural chirality in the beetle shells. The detailed features of each spectral classification are related to different structural perturbations of the helix, including various pitch values and abrupt twist defects. These spectral characteristics and associated shell structures are confirmed on the basis of simple modelling. An important conclusion from our study is that the simple helical structure resulting in a single symmetric Bragg peak is not the dominant spectral type. Rather the reality is a rich tapestry of spectral types. One intriguing specimen is identified via a scanning electron micrograph to consist of a double interstitial helix leading to a particular double-peak spectrum. © 2016 The Authors.

  2. Arctic Riverine CDOM and its effects on the Polar Marine Light Field

    Energy Technology Data Exchange (ETDEWEB)

    Orandle, Zoe Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weijer, Wilbert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Elliott, Scott M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Shanlin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-28

    It is well-known that CDOM (Chromophoric Dissolved Organic Matter) can have a significant effect on biological activity in the photic zones of aquatic ecosystems. However, the extent of CDOM’s interference with biological activity is not well-known. We examined this issue in great detail in the mixed surface layer of the Arctic Ocean. We studied the impacts of CDOM’s light attenuation on Arctic phytoplankton populations to discover if riverine CDOM’s presence in the Arctic ocean could inhibit and possibly prevent local phytoplankton populations from performing photosynthesis. We incorporated biogeochemistry concepts and data with oceanographic models and calculations to approach the problem. The results showed that riverine CDOM can indeed significantly impact the productivity of phytoplankton populations during the spring and summer months near the major Arctic river mouths we chose to examine. Although our study was detailed and inclusive of many variables, the issue of CDOM’s light attenuation and its effects on phytoplankton populations must be explored on a global scale to help understand if riverine CDOM could prove disastrous for phytoplankton populations.

  3. The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones

    Directory of Open Access Journals (Sweden)

    N. Cassar

    2011-02-01

    Full Text Available The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ and the northern reaches of the Polar Frontal Zone (PFZ, we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense study, which occurred in January–February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m−2 d−1. NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m, dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. The strong correlation between NCP and dissolved Fe may be difficult to interpret because of the correlation of dissolved Fe to MLD and because the concentration of iron may not be a good indicator of its availability. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer.

  4. Calculated Hanle transmission and absorption spectra of the 87Rb D1 line with residual magnetic field for arbitrarily polarized light

    International Nuclear Information System (INIS)

    Noh, Heung-Ryoul; Moon, Han Seb

    2010-01-01

    This paper reports a theoretical study on the transmission spectra of an arbitrarily polarized laser beam through a rubidium cell with or without a buffer gas in Hanle-type coherent population trapping (CPT). This study examined how laser polarization, transverse magnetic field, and collisions with buffer gas affects the spectrum. The transmission spectrum due to CPT and the absorption spectrum due to the level crossing absorption (LCA) were calculated according to the laser polarization. The results show that the LCA is strongly dependent on the transverse magnetic field and interaction time of the atoms with a laser light via collisions with the buffer gas. In addition, the spectral shape of the calculated Hanle spectrum is closely related to the direction between the (stray) transverse magnetic field and polarization of the laser.

  5. Assessment Of Mold-Design Dependent Textures In CIM-Components By Polarized Light Optical Texture Analysis (PLOTA)

    International Nuclear Information System (INIS)

    Kern, Frank; Rauch, Johannes; Gadow, Rainer

    2007-01-01

    By thermoplastic ceramic injection moulding (CIM) ceramic components of high complexity can be produced in a large number of items at low dimensional tolerances. The cost advantage by the high degree of automation leads to an economical mass-production. The structure of injection-moulded components is determined by the form filling behaviour and viscosity of the feedstock, the machine parameters, the design of the mold and the gate design. With an adapted mold- and gate-design CIM-components without textures are possible. The ''Polarized Light Optical Texture analysis'' (PLOTA) makes it possible to inspect the components and detect and quantify the textures produced by a new mold. Based on the work of R. Fischer (2004) the PLOTA procedure was improved by including the possibility to measure the inclination angle and thus describe the orientation of the grains in three dimensions. Sampled thin sections of ceramic components are analysed under the polarization microscope and are brought in diagonal position. Pictures are taken with a digital camera. The pictures are converted in the L*a*b*- colour space and the crystals color values a* and b* in the picture are measured. The color values are compared with the values of a quartz wedge, which serves as universal standard. From the received values the inclination angle can be calculated relative to the microscope axis. It is possible to use the received data quantitatively e.g. for the FEM supported simulation of texture-conditioned divergences of mechanical values. Thus the injection molding parameters can be optimized to obtain improved mechanical properties

  6. Evolutionary adaptations of plant AGC kinases: from light signaling to cell polarity regulation

    Directory of Open Access Journals (Sweden)

    Eike Hendrik Rademacher

    2012-11-01

    Full Text Available Signaling and trafficking over membranes involves a plethora of transmembrane proteins that control the flow of compounds or relay specific signaling events. Next to external cues internal stimuli can modify the activity or abundance of these proteins at the plasma membrane. One such regulatory mechanism is protein phosphorylation by membrane-associated kinases and phosphatases. The AGC kinase family is one of seven kinase families that are conserved in all eukaryotic genomes. In plants evolutionary adaptations introduced specific structural changes within the plant AGC kinases that most likely allow for sensing of external stimuli (i.e. light through controlled modification of kinase activity.Starting from the well-defined structural basis common to all AGC kinases we review the current knowledge on the structure-function relationship in plant AGC kinases. Nine of the 39 Arabidopsis AGC kinases have now been shown to be involved in the regulation of auxin transport. In particular, AGC kinase-mediated phosphorylation of the auxin transporters ABCB1 and ABCB19 has been shown to regulate their activity, while auxin transporters of the PIN family are located to different positions at the plasma membrane depending on their phosphorylation status, which is a result of counteracting AGC kinase and PP2A phosphatase activities. We therefore focus on regulation of AGC kinase activity in this context. Identified structural adaptations of the involved AGC kinases may provide new insight into AGC kinase functionality and demonstrate their position as central hubs in the cellular network controlling plant development and growth.

  7. Photoorientation of a liquid-crystalline polyester with azobenzene side groups: Effects of irradiation with linearly polarized red light after photochemical pretreatment

    DEFF Research Database (Denmark)

    Zebger, Ingo; Rutloh, Michael; Hoffmann, Uwe

    2003-01-01

    light. The polyester is characterized by smectic and nematic phases g24SX26SA34N46i and a strong tendency to form J-aggregates. The process requires a photochemical pretreatment by irradiation with UV light or an exposure to visible light of high power density to produce a certain concentration of the Z......In contrast to the conventional photoorientation process with blue light, an orientation of 4-cyano-4'-alkoxyazobenzene side groups parallel to the electric field vector of the incident light is generated upon irradiating films of a liquid-crystalline side-chain polymer with linearly polarized red......-isomer, which destroys any initial orientational order and J-aggregates. The orientation process is cooperative, whereas the light-induced orientation of the photochromic moiety causes an ordering of the alkylene spacers and even of the main-chain segments into the same direction. The most probable mechanism...

  8. Polarized Light from the Sun: Unification of the Corona and Analysis of the Second Solar Spectrum — Further Implications of a Liquid Metallic Hydrogen Solar Model

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2015-07-01

    Full Text Available In order to account for the slight polarization of the continuum towards the limb, propo- nents of the Standard Solar Model (SSM must have recourse to electron or hydrogen- based scattering of light, as no other mechanism is possible in a gaseous Sun. Con- versely, acceptance that the solar body is comprised of condensed matter opens up new avenues in the analysis of this problem, even if the photospheric surface itself is viewed as incapable of emitting polarized light. Thus, the increased disk polarization, from the center to the limb, can be explained by invoking the scattering of light by the at- mosphere above the photosphere. The former is reminiscent of mechanisms which are known to account for the polarization of sunlight in the atmosphere of the Earth. Within the context of the Liquid Metallic Hydrogen Solar Model (LMHSM, molecules and small particles, not electrons or hydrogen atoms as required by the SSM, would primarily act as scattering agents in regions also partially comprised of condensed hy- drogen structures (CHS. In addition, the well-known polarization which characterizes the K-corona would become a sign of emission polarization from an anisotropic source, without the need for scattering. In the LMHSM, the K, F, and T- coronas can be viewed as emissive and reflective manifestations of a single corona l entity adopting a radially anisotropic structure, while slowly cooling with altitude above the photosphere. The presence of “dust particles”, advanced by proponents of the SSM, would no longer be required to explain the F and T-corona, as a single cooling structure would account for the properties of the K, F, and T coronas. At the same time, the polarized “Second Solar Spectrum”, characterized by the dominance of certain elemental or ionic spectral lines and an abundance of molecular lines, could be explained in the LMHSM, by first invoking interface polarization and coordination of these species with condensed matter

  9. Evidence of a circularly polarized light mode along the optic axis in c-cut NH4H2PO4, induced by circular differential reflection and anomalous birefringence

    International Nuclear Information System (INIS)

    Kaminsky, Werner; Steininger, Steven; Herreros-Cedres, Javier; Glazer, Anthony Michael

    2010-01-01

    The anomalous birefringence and circular differential reflection of NH 4 H 2 PO 4 (4-bar2m), cut on the optic axis, have been found to cause an additional signal in measurements of the optical rotation employing polarized light technology, with the sample between crossed and slightly modulated linear polarizers (tilting high accuracy universal polarimetry). The azimuthal rotation of the linearly polarized light, up to 100 times larger than expected, is described in terms of a circularly polarized light mode along the optic axis of varying amplitude. Experimental evidence leading to our conclusion is given and a qualitative model for the effect is presented.

  10. Quantitative characterization of carbon/carbon composites matrix texture based on image analysis using polarized light microscope.

    Science.gov (United States)

    Li, Yixian; Qi, Lehua; Song, Yongshan; Hou, Xianghui; Li, Hejun

    2015-10-01

    A quantitative characteristic method was proposed for characterizing the matrix texture of carbon/carbon(C/C) composites, which determined the mechanical and physical properties of C/C composites. Based on the cloud theory that was commonly used for uncertain reasoning and the transformation between quantitative and qualitative characterization, so the relationship between the extinction angle and texture types was built by the cloud models for describing the texture of microstructure, moreover, linguistic controllers were established to analyze the matrix texture in accordance with the features of the polarized light microscope (PLM) image. On this basis, the extinction angle could be calculated from the PLM image of the C/C composites. In contrast to the results of measurement, the errors between calculative values and measured values were maintained 1-2° in basically. Meanwhile, the PLM image of C/C composites was segmented by the component, in particular, the matrix with mixed textures was further segmented by the difference of texture. It means that the quantitative characterization of C/C composites matrix based on single PLM image has been realized. © 2015 Wiley Periodicals, Inc.

  11. Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained.

    Science.gov (United States)

    Haugan, E; Holst, B

    2013-11-01

    The identification of bast fibre samples, in particular, bast fibres used in textiles, is an important issue in archaeology, criminology and other scientific fields. One of the characteristic features of bast fibres is their fibrillar orientation, referred to as Z- or S twist (or alternatively right- and left-handed fibres). An empirical test for determining the fibrillar orientation using polarized light microscopy has been known in the community for many years. It is referred to as the modified Herzog test or red plate test. The test has the reputation for never producing false results, but also for occasionally not working. However, so far, no proper justification has been provided in the literature that the 'no false results' assumption is really correct and it has also not been clear up till now, why the method sometimes does not work. In this paper, we present an analytical model for the modified Herzog test, which explains why the test never gives a false result. We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  12. Generation of circularly polarized radiation from a compact plasma-based extreme ultraviolet light source for tabletop X-ray magnetic circular dichroism studies

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Daniel; Rudolf, Denis, E-mail: d.rudolf@fz-juelich.de; Juschkin, Larissa [RWTH Aachen University, Experimental Physics of EUV, Steinbachstraße 15, 52074 Aachen (Germany); Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-9), JARA-FIT, 52425 Jülich (Germany); Weier, Christian; Adam, Roman; Schneider, Claus M. [Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), JARA-FIT, 52425 Jülich (Germany); Winkler, Gerrit; Frömter, Robert [Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg (Germany); Danylyuk, Serhiy [RWTH Aachen University, Chair for Technology of Optical Systems, JARA-FIT, Steinbachstraße 15, 52074 Aachen (Germany); Bergmann, Klaus [Fraunhofer Institute for Laser Technology, Steinbachstrasse 15, 52074 Aachen (Germany); Grützmacher, Detlev [Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-9), JARA-FIT, 52425 Jülich (Germany)

    2014-10-15

    Generation of circularly polarized light in the extreme ultraviolet (EUV) spectral region (about 25 eV–250 eV) is highly desirable for applications in spectroscopy and microscopy but very challenging to achieve in a small-scale laboratory. We present a compact apparatus for generation of linearly and circularly polarized EUV radiation from a gas-discharge plasma light source between 50 eV and 70 eV photon energy. In this spectral range, the 3p absorption edges of Fe (54 eV), Co (60 eV), and Ni (67 eV) offer a high magnetic contrast often employed for magneto-optical and electron spectroscopy as well as for magnetic imaging. We simulated and designed an instrument for generation of linearly and circularly polarized EUV radiation and performed polarimetric measurements of the degree of linear and circular polarization. Furthermore, we demonstrate first measurements of the X-ray magnetic circular dichroism at the Co 3p absorption edge with a plasma-based EUV light source. Our approach opens the door for laboratory-based, element-selective spectroscopy of magnetic materials and spectro-microscopy of ferromagnetic domains.

  13. Optical anisotropy of polyimide and polymethacrylate containing photocrosslinkable chalcone group in the side chain under irradiation of a linearly polarized UV light

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dong Hoon; Cha, Young Kwan [Kyunghee Univ., Yongin (Korea, Republic of)

    2002-03-01

    Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy.The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  14. Optical anisotropy of polyimide and polymethacrylate containing photocrosslinkable chalcone group in the side chain under irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy.The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

  15. Comparing the effects of exercise program and low-level laser therapy with exercise program and polarized polychromatic non-coherent light (bioptron light) on the treatment of lateral elbow tendinopathy.

    Science.gov (United States)

    Stasinopoulos, Dimitrios; Stasinopoulos, Ioannis; Pantelis, Manias; Stasinopoulou, Kalliopi

    2009-06-01

    The use of low-level laser therapy (LLLT) and polarized polychromatic non-coherent light as supplements to an exercise program has been recommended for the management of lateral elbow tendinopathy (LET). To investigate whether an exercise program supplemented with LLLT is more successful than an exercise program supplemented with polarized polychromatic non-coherent light in treating LET. Patients with unilateral LET for at least 4 wk were sequentially allocated to receive either an exercise program with LLLT or an exercise program with polarized polychromatic non-coherent light. The exercise program consisted of eccentric and static stretching exercises of wrist extensors. In the LLLT group a 904-nm Ga-As laser was used in continuous mode, and the power density was 130 mW/cm(2), and the dose was 0.585 J/point. In the group receiving polarized polychromatic non-coherent light the Bioptron 2 was used to administer the dose perpendicularly to the lateral epicondyle at three points at an operating distance of 5-10 cm for 6 min at each position. The outcome measures were pain and function and were evaluated at baseline, at the end of the treatment (week 4), and 3 mo after the end of treatment (week 16). Fifty patients met the inclusion criteria. At the end of treatment there was a decline in pain and a rise in function in both groups compared with baseline (p 0.0005 on the independent t-test). The results suggest that the combination of an exercise program with LLLT or polarized polychromatic non-coherent light is an adequate treatment for patients with LET. Further research to establish the relative and absolute effectiveness of such a treatment approach is needed.

  16. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  17. Polarized light field microscopy: an analytical method using a microlens array to simultaneously capture both conoscopic and orthoscopic views of birefringent objects.

    Science.gov (United States)

    Oldenbourg, R

    2008-09-01

    For the comprehensive analysis of anisotropic materials, a new approach, called 'polarized light field microscopy' is introduced. It uses an LC-PolScope to which a microlens array was added at the image plane of the objective lens. The system is patterned after the 'light field microscope' that achieves both lateral and axial resolution in thick specimens in a single camera exposure. In polarized light field microscopy, the microlens array generates a hybrid image consisting of an array of small conoscopic images, each sampling a different object area. Analysis of the conoscopic images reveals the birefringence of each object area as a function of the propagation direction of transmitted light rays. The principles and utility of the instrument that we are calling 'light field LC-PolScope' are demonstrated with images of a thin, polycrystalline calcite film, revealing the azimuth and inclination angle of the optic axis for many crystals simultaneously, including crystals with diameters as small as 2 microm. Compared to traditional conoscopy and related methods, the vastly improved throughput and quantitative analysis afforded by the light field LC-PolScope make it the instrument of choice for measuring 3D birefringence parameters of complex structures.

  18. Polarized light field microscopy: an analytical method using a microlens array to simultaneously capture both conoscopic and orthoscopic views of birefringent objects

    Science.gov (United States)

    Oldenbourg, Rudolf

    2008-01-01

    For the comprehensive analysis of anisotropic materials, a new approach, called “polarized light field microscopy” is introduced. It uses an LC-PolScope to which a microlens array was added at the image plane of the objective lens. The system is patterned after the “light field microscope” that achieves both lateral and axial resolution in thick specimens in a single camera exposure. In polarized light field microscopy, the microlens array generates a hybrid image consisting of an array of small conoscopic images, each sampling a different object area. Analysis of the conoscopic images reveals the birefringence of each object area as a function of the propagation direction of transmitted light rays. The principles and utility of the instrument that we are calling “light field LC-PolScope” are demonstrated with images of a thin, polycrystalline calcite film, revealing the azimuth and inclination angle of the optic axis for many crystals simultaneously, including crystals with diameters as small as 2 µm. Compared to traditional conoscopy and related methods, the vastly improved throughput and quantitative analysis afforded by the light field LC-PolScope make it the instrument of choice for measuring 3-dimensional birefringence parameters of complex structures. PMID:18754996

  19. How Can Polarization States of Reflected Light from Snow Surfaces Inform Us on Surface Normals and Ultimately Snow Grain Size Measurements?

    Science.gov (United States)

    Schneider, A. M.; Flanner, M.; Yang, P.; Yi, B.; Huang, X.; Feldman, D.

    2016-12-01

    The Snow Grain Size and Pollution (SGSP) algorithm is a method applied to Moderate Resolution Imaging Spectroradiometer data to estimate snow grain size from space-borne measurements. Previous studies validate and quantify potential sources of error in this method, but because it assumes flat snow surfaces, however, large scale variations in surface normals can cause biases in its estimates due to its dependence on solar and observation zenith angles. To address these variations, we apply the Monte Carlo method for photon transport using data containing the single scattering properties of different ice crystals to calculate polarization states of reflected monochromatic light at 1500nm from modeled snow surfaces. We evaluate the dependence of these polarization states on solar and observation geometry at 1500nm because multiple scattering is generally a mechanism for depolarization and the ice crystals are relatively absorptive at this wavelength. Using 1500nm thus results in a higher number of reflected photons undergoing fewer scattering events, increasing the likelihood of reflected light having higher degrees of polarization. In evaluating the validity of the model, we find agreement with previous studies pertaining to near-infrared spectral directional hemispherical reflectance (i.e. black-sky albedo) and similarities in measured bidirectional reflectance factors, but few studies exist modeling polarization states of reflected light from snow surfaces. Here, we present novel results pertaining to calculated polarization states and compare dependences on solar and observation geometry for different idealized snow surfaces. If these dependencies are consistent across different ice particle shapes and sizes, then these findings could inform the SGSP algorithm by providing useful relationships between measurable physical quantities and solar and observation geometry to better understand variations in snow surface normals from remote sensing observations.

  20. NON-RACEMIC AMINO ACID PRODUCTION BY ULTRAVIOLET IRRADIATION OF ACHIRAL INTERSTELLAR ICE ANALOGS WITH CIRCULARLY POLARIZED LIGHT

    International Nuclear Information System (INIS)

    De Marcellus, Pierre; Nuevo, Michel; Danger, Gregoire; Deboffle, Dominique; Le Sergeant d'Hendecourt, Louis; Meinert, Cornelia; Filippi, Jean-Jacques; Meierhenrich, Uwe J.; Nahon, Laurent

    2011-01-01

    The delivery of organic matter to the primitive Earth via comets and meteorites has long been hypothesized to be an important source for prebiotic compounds such as amino acids or their chemical precursors that contributed to the development of prebiotic chemistry leading, on Earth, to the emergence of life. Photochemistry of inter/circumstellar ices around protostellar objects is a potential process leading to complex organic species, although difficult to establish from limited infrared observations only. Here we report the first abiotic cosmic ice simulation experiments that produce species with enantiomeric excesses (e.e.'s). Circularly polarized ultraviolet light (UV-CPL) from a synchrotron source induces asymmetric photochemistry on initially achiral inter/circumstellar ice analogs. Enantioselective multidimensional gas chromatography measurements show significant e.e.'s of up to 1.34% for ( 13 C)-alanine, for which the signs and absolute values are related to the helicity and number of CPL photons per deposited molecule. This result, directly comparable with some L excesses measured in meteorites, supports a scenario in which exogenous delivery of organics displaying a slight L excess, produced in an extraterrestrial environment by an asymmetric astrophysical process, is at the origin of biomolecular asymmetry on Earth. As a consequence, a fraction of the meteoritic organic material consisting of non-racemic compounds may well have been formed outside the solar system. Finally, following this hypothesis, we support the idea that the protosolar nebula has indeed been formed in a region of massive star formation, regions where UV-CPL of the same helicity is actually observed over large spatial areas.

  1. Detection of Calcium Crystals in Knee Osteoarthritis Synovial Fluid: A Comparison Between Polarized Light and Scanning Electron Microscopy.

    Science.gov (United States)

    Frallonardo, Paola; Oliviero, Francesca; Peruzzo, Luca; Tauro, Leonardo; Scanu, Anna; Galozzi, Paola; Ramonda, Roberta; Punzi, Leonardo

    2016-10-01

    The identification of calcium crystals in synovial fluid (SF) of patients with osteoarthritis (OA) represents an important step in understanding the role of these crystals in synovial inflammation and disease progression. This study aimed to investigate the presence of calcium pyrophosphate (CPP) and basic calcium phosphate (BCP) crystals in SF collected from patients with symptomatic knee OA by scanning electron microscopy (SEM) coupled to x-ray energy dispersive spectroscopy, compensated polarized light microscopy (CPLM), and alizarin red staining. Seventy-four patients with knee OA were included in the study. Synovial fluid samples were collected after arthrocentesis and examined under CPLM for the assessment of CPP crystals. Basic calcium phosphate crystals were evaluated by alizarin red staining. All the samples were examined by SEM. The concordance between the 2 techniques was evaluated by Cohen κ agreement coefficient. Calcium pyrophosphate and BCP crystals were found, respectively, in 23 (31.1%) and 13 (17.5%) of 74 OA SFs by SEM analysis. Calcium pyrophosphate crystals were identified in 23 (31.1%) of 74 samples by CPLM, whereas BCP crystals were suspected in 27 (36.4%) of 74 samples. According to κ coefficient, the concordance between CPLM and SEM was 0.83 for CPP, and that between alizarin red and SEM was 0.68 for BCP. The results of our study showed a high level of concordance between the 2 microscope techniques as regards CPP crystal identification and a lower agreement for BCP crystals. Although this finding highlights the difficulty in identifying BCP crystals by alizarin red staining, the use of SEM remains unsuitable to apply in the clinical setting. Because of the in vitro inflammatory effect of BCP crystals, further work on their analysis in SF could provide important information about the OA process.

  2. Lighting

    Data.gov (United States)

    Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...

  3. Light

    DEFF Research Database (Denmark)

    Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

    2004-01-01

    This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

  4. How can horseflies be captured by solar panels? A new concept of tabanid traps using light polarization and electricity produced by photovoltaics.

    Science.gov (United States)

    Blahó, Miklós; Egri, Ádám; Barta, András; Antoni, Györgyi; Kriska, György; Horváth, Gábor

    2012-10-26

    Horseflies (Diptera: Tabanidae) can cause severe problems for humans and livestock because of the continuous annoyance performed and the diseases vectored by the haematophagous females. Therefore, effective horsefly traps are in large demand, especially for stock-breeders. To catch horseflies, several kinds of traps have been developed, many of them attracting these insects visually with the aid of a black ball. The recently discovered positive polarotaxis (attraction to horizontally polarized light) in several horsefly species can be used to design traps that capture female and male horseflies. The aim of this work is to present the concept of such a trap based on two novel principles: (1) the visual target of the trap is a horizontal solar panel (photovoltaics) attracting polarotactic horseflies by means of the highly and horizontally polarized light reflected from the photovoltaic surface. (2) The horseflies trying to touch or land on the photovoltaic trap surface are perished by the mechanical hit of a wire rotated quickly with an electromotor supplied by the photovoltaics-produced electricity. Thus, the photovoltaics is bifunctional: its horizontally polarized reflected light signal attracts water-seeking, polarotactic horseflies, and it produces the electricity necessary to rotate the wire. We describe here the concept and design of this new horsefly trap, the effectiveness of which was demonstrated in field experiments. The advantages and disadvantages of the trap are discussed. Using imaging polarimetry, we measured the reflection-polarization characteristics of the photovoltaic trap surface demonstrating the optical reason for the polarotactic attractiveness to horseflies. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Symmetry relationships for multiple scattering of polarized light in turbid spherical samples: theory and a Monte Carlo simulation.

    Science.gov (United States)

    Otsuki, Soichi

    2016-02-01

    This paper presents a theory describing totally incoherent multiple scattering of turbid spherical samples. It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in spherical samples. Monte Carlo simulations generate a reduced effective scattering Mueller matrix, which virtually satisfies reciprocity and mirror symmetry. The scattering matrix was factorized by using the symmetric decomposition in a predefined form, as well as the Lu-Chipman polar decomposition, approximately into a product of a pure depolarizer and vertically oriented linear retarding diattenuators. The parameters of these components were calculated as a function of the polar angle. While the turbid spherical sample is a pure depolarizer at low polar angles, it obtains more functions of the retarding diattenuator with increasing polar angle.

  6. States of maximum polarization for a quantum light field and states of a maximum sensitivity in quantum interferometry

    International Nuclear Information System (INIS)

    Peřinová, Vlasta; Lukš, Antonín

    2015-01-01

    The SU(2) group is used in two different fields of quantum optics, the quantum polarization and quantum interferometry. Quantum degrees of polarization may be based on distances of a polarization state from the set of unpolarized states. The maximum polarization is achieved in the case where the state is pure and then the distribution of the photon-number sums is optimized. In quantum interferometry, the SU(2) intelligent states have also the property that the Fisher measure of information is equal to the inverse minimum detectable phase shift on the usual simplifying condition. Previously, the optimization of the Fisher information under a constraint was studied. Now, in the framework of constraint optimization, states similar to the SU(2) intelligent states are treated. (paper)

  7. The polarization of light in coastal and open oceans: Reflection and transmission by the air-sea interface and application for the retrieval of water optical properties

    Science.gov (United States)

    Foster, Robert

    For decades, traditional remote sensing retrieval methods that rely solely on the spectral intensity of the water-leaving light have provided indicators of aquatic ecosystem health. With the increasing demand for new water quality indicators and improved accuracy of existing ones, the limits of traditional remote sensing approaches are becoming apparent. Use of the additional information intrinsic to the polarization state of light is therefore receiving more attention. One of the major challenges inherent in any above-surface determination of the water-leaving radiance, scalar or vector, is the removal of extraneous light which has not interacted with the water body and is therefore not useful for remote sensing of the water itself. Due in-part to the lack of a proven alternative, existing polarimeter installations have thus far assumed that such light was reflected by a flat sea surface, which can lead to large inaccuracies in the water-leaving polarization signal. This dissertation rigorously determines the full Mueller matrices for both surface-reflected skylight and upwardly transmitted light by a wind-driven ocean surface. A Monte Carlo code models the surface in 3D and performs polarized ray-tracing, while a vector radiative transfer (VRT) simulation generates polarized light distributions from which the initial Stokes vector for each ray is inferred. Matrices are computed for the observable range of surface wind speeds, viewing and solar geometries, and atmospheric aerosol loads. Radiometer field-of-view effects are also assessed. Validation of the results is achieved using comprehensive VRT simulations of the atmosphere-ocean system based on several oceanographic research cruises and specially designed polarimeters developed by the City College of New York: one submerged beneath the surface and one mounted on a research vessel. When available, additional comparisons are made at 9 km altitude with the NASA Research Scanning Polarimeter (RSP). Excellent

  8. Effects of a chronic reduction of short-wavelength light input on melatonin and sleep patterns in humans: evidence for adaptation.

    Science.gov (United States)

    Giménez, Marina C; Beersma, Domien G M; Bollen, Pauline; van der Linden, Matthijs L; Gordijn, Marijke C M

    2014-06-01

    Light is an important environmental stimulus for the entrainment of the circadian clock and for increasing alertness. The intrinsically photosensitive ganglion cells in the retina play an important role in transferring this light information to the circadian system and they are elicited in particular by short-wavelength light. Exposure to short wavelengths is reduced, for instance, in elderly people due to yellowing of the ocular lenses. This reduction may be involved in the disrupted circadian rhythms observed in aged subjects. Here, we tested the effects of reduced blue light exposure in young healthy subjects (n = 15) by using soft orange contact lenses (SOCL). We showed (as expected) that a reduction in the melatonin suppressing effect of light is observed when subjects wear the SOCL. However, after chronic exposure to reduced (short wavelength) light for two consecutive weeks we observed an increase in sensitivity of the melatonin suppression response. The response normalized as if it took place under a polychromatic light pulse. No differences were found in the dim light melatonin onset or in the amplitude of the melatonin rhythms after chronic reduced blue light exposure. The effects on sleep parameters were limited. Our results demonstrate that the non-visual light system of healthy young subjects is capable of adapting to changes in the spectral composition of environmental light exposure. The present results emphasize the importance of considering not only the short-term effects of changes in environmental light characteristics.

  9. Polarized light microscopy of hair shafts aids in the differential diagnosis of Chédiak-Higashi and Griscelli-Prunieras syndromes Contribuição do estudo dos cabelos com microscopia de luz polarizada ao diagnóstico diferencial das síndromes de Chédiak-Higashi and Grisceli-Prunieras

    OpenAIRE

    Neusa Y.S. Valente; Maria Cecilia M.R. Machado; Paula Boggio; Ana Cristina F. Alves; Fabiane N. Bergonse; Erasmo Casella; Dewton Moraes Vasconcelos; Anete S. Grumach; Zilda N.P. de Oliveira

    2006-01-01

    PURPOSE: To study and compare the appearance of hairs from patients with Chédiak-Higashi and Griscelli-Prunieras syndromes under light and polarized light microscopy. METHOD: Hairs from 2 Chédiak-Higashi and 2 Griscelli-Prunieras patients were obtained and examined under normal and polarized light microscopy. RESULTS: Under light microscopy, hairs from Chédiak-Higashi patients presented evenly distributed, regular melanin granules, larger than those seen in normal hairs. Under polarized light...

  10. Hierarchical super-structure identified by polarized light microscopy, electron microscopy and nanoindentation: Implications for the limits of biological control over the growth mode of abalone sea shells

    Directory of Open Access Journals (Sweden)

    Schneider Andreas S

    2012-09-01

    Full Text Available Abstract Background Mollusc shells are commonly investigated using high-resolution imaging techniques based on cryo-fixation. Less detailed information is available regarding the light-optical properties. Sea shells of Haliotis pulcherina were embedded for polishing in defined orientations in order to investigate the interface between prismatic calcite and nacreous aragonite by standard materialographic methods. A polished thin section of the interface was prepared with a defined thickness of 60 μm for quantitative birefringence analysis using polarized light and LC-PolScope microscopy. Scanning electron microscopy images were obtained for comparison. In order to study structural-mechanical relationships, nanoindentation experiments were performed. Results Incident light microscopy revealed a super-structure in semi-transparent regions of the polished cross-section under a defined angle. This super-structure is not visible in transmitted birefringence analysis due to the blurred polarization of small nacre platelets and numerous organic interfaces. The relative orientation and homogeneity of calcite prisms was directly identified, some of them with their optical axes exactly normal to the imaging plane. Co-oriented "prism colonies" were identified by polarized light analyses. The nacreous super-structure was also visualized by secondary electron imaging under defined angles. The domains of the super-structure were interpreted to consist of crystallographically aligned platelet stacks. Nanoindentation experiments showed that mechanical properties changed with the same periodicity as the domain size. Conclusions In this study, we have demonstrated that insights into the growth mechanisms of nacre can be obtained by conventional light-optical methods. For example, we observed super-structures formed by co-oriented nacre platelets as previously identified using X-ray Photo-electron Emission Microscopy (X-PEEM [Gilbert et al., Journal of the

  11. Photo-alignment of low-molecular mass nematic liquid crystals on photochemically bifunctional chalcone-epoxy film by irradiation of a linearly polarized UV light

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Dong Hoon; Cha, Young Kwan [Kyunghee Univ., Yongin (Korea, Republic of)

    2002-04-01

    Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthesized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photo initiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization . Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

  12. Structural and optical properties of semi-polar (11-22) InGaN/GaN green light-emitting diode structure

    Science.gov (United States)

    Zhao, Guijuan; Wang, Lianshan; Li, Huijie; Meng, Yulin; Li, Fangzheng; Yang, Shaoyan; Wang, Zhanguo

    2018-01-01

    Semi-polar (11-22) InGaN multiple quantum well (MQW) green light-emitting diode (LED) structures have been realized by metal-organic chemical vapor deposition on an m-plane sapphire substrate. By introducing double GaN buffer layers, we improve the crystal quality of semi-polar (11-22) GaN significantly. The vertical alignment of the diffraction peaks in the (11-22) X-ray reciprocal space mapping indicates the fully strained MQW on the GaN layer. The photoluminescence spectra of the LED structure show stronger emission intensity along the [1-100] InGaN/GaN direction. The electroluminescence emission of the LED structure is very broad with peaks around 550 nm and 510 nm at the 100 mA current injection for samples A and B, respectively, and exhibits a significant blue-shift with increasing drive current.

  13. Photo-alignment of low-molecular mass nematic liquid crystals on photochemically bifunctional chalcone-epoxy film by irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthesized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photo initiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization . Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

  14. Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation.

    Science.gov (United States)

    Enomoto, Gen; Ni-Ni-Win; Narikawa, Rei; Ikeuchi, Masahiko

    2015-06-30

    Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors that have diverse spectral properties and domain compositions. Although large numbers of CBCR genes exist in cyanobacterial genomes, no studies have assessed whether multiple CBCRs work together. We recently showed that the diguanylate cyclase (DGC) activity of the CBCR SesA from Thermosynechococcus elongatus is activated by blue-light irradiation and that, when irradiated, SesA, via its product cyclic dimeric GMP (c-di-GMP), induces aggregation of Thermosynechococcus vulcanus cells at a temperature that is suboptimum for single-cell viability. For this report, we first characterize the photobiochemical properties of two additional CBCRs, SesB and SesC. Blue/teal light-responsive SesB has only c-di-GMP phosphodiesterase (PDE) activity, which is up-regulated by teal light and GTP. Blue/green light-responsive SesC has DGC and PDE activities. Its DGC activity is enhanced by blue light, whereas its PDE activity is enhanced by green light. A ΔsesB mutant cannot suppress cell aggregation under teal-green light. A ΔsesC mutant shows a less sensitive cell-aggregation response to ambient light. ΔsesA/ΔsesB/ΔsesC shows partial cell aggregation, which is accompanied by the loss of color dependency, implying that a nonphotoresponsive DGC(s) producing c-di-GMP can also induce the aggregation. The results suggest that SesB enhances the light color dependency of cell aggregation by degrading c-di-GMP, is particularly effective under teal light, and, therefore, seems to counteract the induction of cell aggregation by SesA. In addition, SesC seems to improve signaling specificity as an auxiliary backup to SesA/SesB activities. The coordinated action of these three CBCRs highlights why so many different CBCRs exist.

  15. A non-local-thermodynamic equilibrium formulation of the transport equation for polarized light in the presence of weak magnetic fields. Doctoral thesis

    International Nuclear Information System (INIS)

    McNamara, D.J.

    1977-01-01

    The present work is motivated by the desire to better understand solar magnetism. Just as stellar astrophysics and radiative transfer have been coupled in the history of research in physics, so too has the study of radiative transfer of polarized light in magnetic fields and solar magnetism been a history of mutual growth. The Stokes parameters characterize the state of polarization of a beam of radiation. The author considers the changes in polarization, and therefore in the Stokes parameters, due to the transport of a beam through an optically thick medium in a weak magnetic field. The transport equation is derived from a general density matrix equation of motion. This allows the possibility of interference effects arising from the mixing of atomic sublevels in a weak magnetic field to be taken into account. The statistical equilibrium equations are similarly derived. Finally, the coupled system of equations is presented, and the order of magnitude of the interference effects, shown. Collisional effects are not considered. The magnitude of the interference effects in magnetic field measurements of the sun may be evaluated

  16. Study of Collagen Birefringence in Different Grades of Oral Squamous Cell Carcinoma Using Picrosirius Red and Polarized Light Microscopy

    Directory of Open Access Journals (Sweden)

    Pillai Arun Gopinathan

    2015-01-01

    Full Text Available Objectives. The present study was done to evaluate birefringence pattern of collagen fibres in different grades of oral squamous cell carcinoma using Picrosirius red stain and polarization microscopy and to determine if there is a change in collagen fibres between different grades of oral squamous cell carcinoma. Materials and Methods. Picrosirius red stained 5 μm thick sections of previously diagnosed different grades of squamous cell carcinoma and normal oral mucosa were studied under polarization microscopy for arrangement as well as birefringence of collagen fibres around tumour islands. Results. It was found that thin collagen fibres increased and thick collagen fibres decreased with dedifferentiation of OSCC (P<0.0001 . It was observed that there was change in polarization colours of thick fibres from yellowish orange to greenish yellow with dedifferentiation of OSCC indicating loosely packed fibres (P<0.0001. Conclusion. There was a gradual change of birefringence of collagen from yellowish orange to greenish yellow from well to poorly differentiated squamous cell carcinoma, indicating that there is a change from mature form of collagen to immature form as tumour progresses. Studying collagen fibres with Picrosirius red for stromal changes around tumour islands along with routine staining may help in predicting the prognosis of tumour.

  17. Difference between the Brewster angle and angle of minimum reflectance for incident unpolarized or circularly polarized light at interfaces between transparent media.

    Science.gov (United States)

    Azzam, R M A

    2015-06-01

    For reflection at interfaces between transparent optically isotropic media, the difference between the Brewster angle ϕB of zero reflectance for incident p-polarized light and the angle ϕu min of minimum reflectance for incident unpolarized or circularly polarized light is considered as function of the relative refractive n in external and internal reflection. We determine the following. (i) ϕu min reflection (n > 1), the maximum difference (ϕB - ϕu min)max = 75° at n = 2 + √3. (iii) In internal reflection and 0 reflectance R0 at normal incidence is in the range 0 ≤ R0 ≤ 1/3, ϕu min = 0, and ϕB - ϕu min = ϕB. (v) For internal reflection and 0 < n < 2 - √3, ϕu min exhibits an unexpected maximum (= 12.30°) at n = 0.24265. Finally, (vi) for 1/3 ≤ R0 < 1, Ru min at ϕu min is limited to the range 1/3 ≤ Ru min < 1/2.

  18. Dominant transverse-electric polarized emission from 298 nm MBE-grown AlN-delta-GaN quantum well ultraviolet light-emitting diodes

    Science.gov (United States)

    Liu, Cheng; Ooi, Yu Kee; Islam, S. M.; Xing, Huili Grace; Jena, Debdeep; Zhang, Jing

    2017-02-01

    III-nitride based ultraviolet (UV) light emitting diodes (LEDs) are of considerable interest in replacing gas lasers and mercury lamps for numerous applications. Specifically, AlGaN quantum well (QW) based LEDs have been developed extensively but the external quantum efficiencies of which remain less than 10% for wavelengths <300 nm due to high dislocation density, difficult p-type doping and most importantly, the physics and band structure from the three degeneration valence subbands. One solution to address this issue at deep UV wavelengths is by the use of the AlGaN-delta-GaN QW where the insertion of the delta-GaN layer can ensure the dominant conduction band (C) - heavyhole (HH) transition, leading to large transverse-electric (TE) optical output. Here, we proposed and investigated the physics and polarization-dependent optical characterizations of AlN-delta- GaN QW UV LED at 300 nm. The LED structure is grown by Molecular Beam Epitaxy (MBE) where the delta-GaN layer is 3-4 monolayer (QW-like) sandwiched by 2.5-nm AlN sub-QW layers. The physics analysis shows that the use of AlN-delta-GaN QW ensures a larger separation between the top HH subband and lower-energy bands, and strongly localizes the electron and HH wave functions toward the QW center and hence resulting in 30-time enhancement in TEpolarized spontaneous emission rate, compared to that of a conventional Al0.35Ga0.65N QW. The polarization-dependent electroluminescence measurements confirm our theoretical analysis; a dominant TE-polarized emission was obtained at 298 nm with a minimum transverse-magnetic (TM) polarized emission, indicating the feasibility of high-efficiency TEpolarized UV emitters based on our proposed QW structure.

  19. Light

    CERN Document Server

    Rivera, Andrea

    2017-01-01

    Light is all around us. Learn how it is used in art, technology, and engineering. Five easy-to-read chapters explain the science behind light, as well as its real-world applications. Vibrant, full-color photos, bolded glossary words, and a key stats section let readers zoom in even deeper. Aligned to Common Core Standards and correlated to state standards. Abdo Zoom is a division of ABDO.

  20. Characterization of process-induced damage in Cu/low-k interconnect structure by microscopic infrared spectroscopy with polarized infrared light

    Energy Technology Data Exchange (ETDEWEB)

    Seki, Hirofumi, E-mail: Hirofumi-Seki@trc.toray.co.jp; Hashimoto, Hideki [Toray Research Center, Inc., 3-3-7 Sonoyama, Otsu, Shiga 520-8567 (Japan); Ozaki, Yukihiro [Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1, Gakuen, Sanda, Hyogo 669-1337 (Japan)

    2016-09-07

    Microscopic Fourier-transform infrared (FT-IR) spectra are measured for a Cu/low-k interconnect structure using polarized IR light for different widths of low-k spaces and Cu lines, and for different heights of Cu lines, on Si substrates. Although the widths of the Cu line and the low-k space are 70 nm each, considerably smaller than the wavelength of the IR light, the FT-IR spectra of the low-k film were obtained for the Cu/low-k interconnect structure. A suitable method was established for measuring the process-induced damage in a low-k film that was not detected by the TEM-EELS (Transmission Electron Microscope-Electron Energy-Loss Spectroscopy) using microscopic IR polarized light. Based on the IR results, it was presumed that the FT-IR spectra mainly reflect the structural changes in the sidewalls of the low-k films for Cu/low-k interconnect structures, and the mechanism of generating process-induced damage involves the generation of Si-OH groups in the low-k film when the Si-CH{sub 3} bonds break during the fabrication processes. The Si-OH groups attract moisture and the OH peak intensity increases. It was concluded that the increase in the OH groups in the low-k film is a sensitive indicator of low-k damage. We achieved the characterization of the process-induced damage that was not detected by the TEM-EELS and speculated that the proposed method is applicable to interconnects with line and space widths of 70 nm/70 nm and on shorter scales of leading edge devices. The location of process-induced damage and its mechanism for the Cu/low-k interconnect structure were revealed via the measurement method.

  1. The use of Bioptron light (polarized, polychromatic, non-coherent) therapy for the treatment of acute ankle sprains.

    Science.gov (United States)

    Stasinopoulos, Dimitrios; Papadopoulos, Costas; Lamnisos, Dimitrios; Stasinopoulos, Ioannis

    2017-03-01

    Purpose The purpose of this study was to investigate the efficacy of Bioptron light therapy for the treatment of acute ankle sprains. Method A parallel group, single-blind, controlled study was carried out in patients with grade II acute ankle sprains. Patients were randomly allocated into two treatment groups (n = 25 for each). Both groups received cryotherapy, and the test group also received Bioptron light therapy. All treatments were performed daily for 5 d. Evaluations included self-reported pain via a visual analogue scale, degree of ankle edema, and ankle range of motion via goniometry carried out before the treatment and at the end of the treatment. Results The test group showed the largest magnitude of improvement for all evaluations at treatment five, and the between-group differences observed were statistically significant (p Bioptron light therapy supplemented with cryotherapy for the treatment of acute ankle sprains; however, larger studies are required to confirm these results. Implications for Rehabilitation Ankle sprains are common acute injuries among professional and recreational sports players but also among people in general. Cryotherapy is the first-standard treatment of acute ankle sprains. Phototherapy such as Bioptron light has been recommended supplement to cryotherapy to reduce the symptoms of ankle sprains. The results of the present trial showed that using BIOPTRON LIGHT and cryotherapy the rehabilitation period of acute ankle sprains can be reduced.

  2. Enhanced two-channel nonlinear imaging by a highly polarized supercontinuum light source generated from a nonlinear photonic crystal fiber with two zero-dispersion wavelengths

    Science.gov (United States)

    Tao, Wei; Bao, Hongchun; Gu, Min

    2011-05-01

    Real-time monitoring the variation of chlorophyll distributions and cellular structures in leaves during plant growth provides important information for understanding the physiological statuses of plants. Two-photon-excited autofluorescence imaging and second harmonic generation imaging of leaves can be used for monitoring the nature intrinsic fluorophores distribution and cellular structures of leaves by the use of the near-infrared region of light which has minimal light absorption by endogenous molecules and thus increases tissue penetration. However, the two-photon absorption peak of intrinsic fluorophores of a ficus benjamina leaf is 50 nm away from the second harmonic generation excitation wavelength, which cannot be effectively excited by a femtosecond laser beam with one central wavelength. This paper shows that a highly polarized supercontinuum light generated from a birefringent nonlinear photonic crystal fiber with two zero-dispersion wavelengths can effectively excite two-photon autofluorescence as well as second harmonic generation signals for simultaneously monitoring intrinsic fluorophore distributions and non-centrosymmetric structures of leaves.

  3. Light

    CERN Document Server

    Ditchburn, R W

    1963-01-01

    This classic study, available for the first time in paperback, clearly demonstrates how quantum theory is a natural development of wave theory, and how these two theories, once thought to be irreconcilable, together comprise a single valid theory of light. Aimed at students with an intermediate-level knowledge of physics, the book first offers a historical introduction to the subject, then covers topics such as wave theory, interference, diffraction, Huygens' Principle, Fermat's Principle, and the accuracy of optical measurements. Additional topics include the velocity of light, relativistic o

  4. Hydrophilic interaction chromatography and evaporative light scattering detection for the determination of polar analytes in Belgian endive.

    Science.gov (United States)

    Annaratone, Carlo; De Roeck, Ans; Hertog, Maarten L A T M; Nicolaï, Bart M

    2017-08-15

    Belgian endive (Cichorium intybus L. var. foliosum Hegi), a popular produce in northern Europe, has been thoroughly studied in regard to its bitter sesquiterpene lactones content. Much less is known about on its sweetness and crunchiness, which are typically linked to the content of polar compounds such as sugars, organic acids and salts. Through HILIC-HPLC-MS, it was shown that simple sugars, amino acids, and potassium chloride are abundant in Belgian endive extracts. Subsequently, a HILIC-HPLC-ELSD method for the analysis of such compounds with run times below six minutes was developed. Recoveries varied between 80 and 110% and an average reproducibility was 7.5RSD%. Finally, the method was applied to the study of three difference Belgian endive varieties. Takine, a variety known for its sweet taste, was found to contain significantly higher levels of fructose, and lower levels of potassium and glutamine. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Red light emission from ZnO:Eu{sup 3+}|CuSCN hetero-junction under cathodic polarization

    Energy Technology Data Exchange (ETDEWEB)

    Sirimanne, P.M., E-mail: psirimane@hotmail.com [Department of Science and Technology, Uwa Wellassa University, Badulla (Sri Lanka); Minoura, H. [Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan)

    2015-09-15

    Eu{sup 3+} ions were bonded to ZnO ceramic via organic ligand. Surface bonded Eu{sup 3+} ions were exhibited specific luminescence bands due to electron transitions between f–f intra-configurationally transitions. Further enhancement of luminescence bands was observed by attaching selected oligomers to Eu{sup 3+} ions. A hetero-junction was prepared by depositing copper-thiocyanate on Eu{sup 3+} ions bonded ZnO ceramic. Red light emission was observed from surface bonded Eu{sup 3+} ions in ZnO:Eu{sup 3+}|CuSCN hetero-junction under reverse bias. - Highlights: • Europium doped ZnO ceramic exhibits photo-luminescence. • Semiconductor hetro-junction was prepared. • ZnO:Eu{sup 3+}|CuSCN hetero-junction emits red light under reverse bias.

  6. [Ozone therapy and phototherapy with polarized polychromatic light in treatment of patients suffering from lower limb critical ischaemia].

    Science.gov (United States)

    Drozhzhin, E V; Sidorkina, O N

    2012-01-01

    The authors generalized their experience in treating a total of 77 patients presenting with atherosclerosis of the arteries of lower limbs with degree III-IV ischaemia according to the A.V. Pokrovsky-Fontain classification. The patients were subjected to comprehensive treatment including the impact of piler-light (apparatus Bioptron 2) and ozone therapy. The control group was composed of 66 people receiving conventional therapy. The two groups were comparable by the nosological entity of the disease, gender, age, and the nature of accompanying pathology. Despite carried out classical anticoagulation therapy there was a tendency towards hypercoagulation in phase I (formation of prothrombinase) and phase III (formation of fibrin) of plasma haemostasis, as well as insufficiency of the fibrinolytic system. The obtained results showed direct influence of ozone therapy and piler light on phase I and III plasmatic haemostasis, as well as enhanced fibrinolytic activity of blood on the background of their administration thereof.

  7. Three-Way-Switchable (Right/Left/OFF) Selective Reflection of Circularly Polarized Light on Solid Thin Films of Helical Polymer Blends.

    Science.gov (United States)

    Nagata, Yuuya; Uno, Makoto; Suginome, Michinori

    2016-06-13

    Two poly(quinoxaline-2,3-diyl) copolymers bearing miscibility-enhancing 8-chlorooctyloxy and (S)-2-methylbutoxy or n-butoxy side chains were synthesized. After annealing in CHCl3 vapor, a polymer-blend film of these copolymers exhibited selective reflection of right-handed circularly polarized light (CPL) in the visible region. The handedness of the CPL reflected was completely inverted upon annealing of the film in THF vapor. Annealing in n-hexane vapor resulted in the phase separation of the polymer blend, which turned the selective reflection off. This three-way-switchable reflection, that is, reflection of right-handed or left-handed CPL, together with an OFF state, could be observed visually through right- and left-handed CPL filters. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Polarized Light Microscopy Study on the Reentrant Phase Transition in a (Ba1 – xKxFe2As2 Single Crystal with x = 0.24

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2016-11-01

    Full Text Available A sequence of structural/magnetic transitions on cooling is reported in the literature for hole-doped iron-based superconductor (Ba1 − xKxFe2As2 with x = 0.24. By using polarized light microscopy, we directly observe the formation of orthorhombic domains in (Ba1 − xKxFe2As2 (x = 0.24 single crystal below a temperature of simultaneous structural/magnetic transition TN ~ 80 K. The structural domains vanish below ~30 K, but reappear below T = 15 K. Our results are consistent with reentrance transformation sequence from high-temperature tetragonal (HTT to low temperature orthorhombic (LTO1 structure at TN ~ 80 K, LTO1 to low temperature tetragonal (LTT structure at Tc ~ 25 K, and LTT to low temperature orthorhombic (LTO2 structure at T ~ 15 K.

  9. Double photoionization of helium at an excess energy of 60 eV using left- and right-elliptically-polarized light

    International Nuclear Information System (INIS)

    Collins, S.A.; Cvejanovic, S.; Dawson, C.; Reddish, T.J.; Seccombe, D.P.; Huetz, A.; Malegat, L.; Selles, P.; Kazansky, A.K.; Danjo, A.; Soejima, K.; Okuno, K.; Yagishita, A.

    2002-01-01

    Helium double photoionization (γ,2e) triple differential cross sections (TDCSs) were measured at an excess energy of 60 eV using a dual toroidal spectrometer and synchrotron radiation from a helical undulator (BL-28A, Photon Factory, Japan). Energy-sharing ratios (R=E 2 /E 1 ) for the two ejected electrons of 5 and 11 are studied with both right- and left-handed elliptically polarized light. The TDCSs are found to be in good agreement with those obtained using the hyperspherical R matrix with semiclassical outgoing waves theory. The circular dichroism for a limited mutual angular range (φ 12 ≅110 deg. -200 deg.) is determined from the experimental data for both R=5 and 11, and compared to theoretical calculations performed over the complete range of mutual angles. No dynamic nodes are found in either the experimental (within the explored φ 12 range) or theoretical circular dichroism for these R values at this excess energy

  10. Broadband measurements of electron cyclotron emission in TFTR [Tokamak Fusion Test Reactor] using a quasi-optical light collection system and a polarizing Michelson interferometer

    International Nuclear Information System (INIS)

    Stauffer, F.J.; Boyd, D.A.; Cutler, R.C.; Diesso, M.; McCarthy, M.P.; Montague, J.; Rocco, R.

    1988-04-01

    For the past three years, a Fourier transform spectrometer diagnostic system, employing a fast-scanning polarizing Michelson interferometer, has been operating on the TFTR tokamak at Princeton Plasma Physics Laboratory. It is used to measure the electron cyclotron emission spectrum over the range 2.5 to 18 cm/sup /minus/1/ (75-540 GHz) with a resolution of 0.123 cm/sup /minus/1/(3.7 GHz), at a rate of 72 spectra per second. The quasi-optical system for collecting the light and transporting it through the interferometer to the detector has been designed using the concepts of both Gaussian and geometrical optics in order to produce a system that is efficient over the entire spectral range. The commerical Michelson interferometer was custom-made for this project and is at the state of the art for this type of specialized instrument. Various pre-installation and post-installation tests of the optical system and the interferometer were performed and are reported here. An error propagation analysis of the absolute calibration process is given. Examples of electron cyclotron emission spectra measured in two polarization directions are given, and electron temperature profiles derived from each of them are compared. 34 refs., 17 figs

  11. Electron and ion angular distributions in resonant dissociative photoionization of H{sub 2} and D{sub 2} using linearly polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Jorge; MartIn, Fernando [Departamento de Quimica C-9, Universidad Autonoma de Madrid, 28049 Madrid (Spain)], E-mail: fernando.martin@uam.es

    2009-04-15

    We have evaluated fully differential electron angular distributions in H{sub 2} and D{sub 2} dissociative photoionization by using linearly polarized light of 20, 27 and 33 eV. At 20 eV, the distributions exhibit simple p-wave patterns, which is the signature of direct ionization through the X{sup 2}{sigma}{sub g}{sup +}(1s{sigma}{sub g}) channel. At 27 eV, where the Q{sub 1} autoionizing states are populated, we observe a similar pattern, except when the molecule is oriented perpendicularly to the polarization direction and the energy of the ejected electron is small. In contrast, at 33 eV, autoionization from the Q{sub 1} and Q{sub 2} states leads to interferences between the X{sup 2}{sigma}{sub g}{sup +}(1s{sigma}{sub g}) and {sup 2}{sigma}{sub u}{sup +}(2p{sigma}{sub u}) ionization channels that result in a strong asymmetry of the electron angular distributions along the molecular axis. This asymmetry changes rapidly with the energy of the ejected electron. Electron angular distributions integrated over all possible molecular orientations or ion angular distributions integrated over electron emission angle show no reminiscence of the above phenomena, but the corresponding asymmetry parameters dramatically change with electron and ion energies in the region of autoionizing states.

  12. Broadband measurements of electron cyclotron emission in TFTR (Tokamak Fusion Test Reactor) using a quasi-optical light collection system and a polarizing Michelson interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, F.J.; Boyd, D.A.; Cutler, R.C.; Diesso, M.; McCarthy, M.P.; Montague, J.; Rocco, R.

    1988-04-01

    For the past three years, a Fourier transform spectrometer diagnostic system, employing a fast-scanning polarizing Michelson interferometer, has been operating on the TFTR tokamak at Princeton Plasma Physics Laboratory. It is used to measure the electron cyclotron emission spectrum over the range 2.5 to 18 cm/sup /minus/1/ (75-540 GHz) with a resolution of 0.123 cm/sup /minus/1/(3.7 GHz), at a rate of 72 spectra per second. The quasi-optical system for collecting the light and transporting it through the interferometer to the detector has been designed using the concepts of both Gaussian and geometrical optics in order to produce a system that is efficient over the entire spectral range. The commerical Michelson interferometer was custom-made for this project and is at the state of the art for this type of specialized instrument. Various pre-installation and post-installation tests of the optical system and the interferometer were performed and are reported here. An error propagation analysis of the absolute calibration process is given. Examples of electron cyclotron emission spectra measured in two polarization directions are given, and electron temperature profiles derived from each of them are compared. 34 refs., 17 figs.

  13. Energy efficiency for the removal of non-polar pollutants during ultraviolet irradiation, visible light photocatalysis and ozonation of a wastewater effluent.

    Science.gov (United States)

    Santiago-Morales, Javier; Gómez, María José; Herrera-López, Sonia; Fernández-Alba, Amadeo R; García-Calvo, Eloy; Rosal, Roberto

    2013-10-01

    This study aims to assess the removal of a set of non-polar pollutants in biologically treated wastewater using ozonation, ultraviolet (UV 254 nm low pressure mercury lamp) and visible light (Xe-arc lamp) irradiation as well as visible light photocatalysis using Ce-doped TiO2. The compounds tracked include UV filters, synthetic musks, herbicides, insecticides, antiseptics and polyaromatic hydrocarbons. Raw wastewater and treated samples were analyzed using stir-bar sorptive extraction coupled with comprehensive two-dimensional gas chromatography (SBSE-CG × GC-TOF-MS). Ozone treatment could remove most pollutants with a global efficiency of over 95% for 209 μM ozone dosage. UV irradiation reduced the total concentration of the sixteen pollutants tested by an average of 63% with high removal of the sunscreen 2-ethylhexyl trans-4-methoxycinnamate (EHMC), the synthetic musk 7-acetyl-1,1,3,4,4,6-hexamethyltetrahydronaphthalene (tonalide, AHTN) and several herbicides. Visible light Ce-TiO2 photocatalysis reached ~70% overall removal with particularly high efficiency for synthetic musks. In terms of power usage efficiency expressed as nmol kJ(-1), the results showed that ozonation was by far the most efficient process, ten-fold over Xe/Ce-TiO2 visible light photocatalysis, the latter being in turn considerably more efficient than UV irradiation. In all cases the efficiency decreased along the treatments due to the lower reaction rate at lower pollutant concentration. The use of photocatalysis greatly improved the efficiency of visible light irradiation. The collector area per order decreased from 9.14 ± 5.11 m(2) m(-3) order(-1) for visible light irradiation to 0.16 ± 0.03 m(2) m(-3) order(-1) for Ce-TiO2 photocatalysis. The toxicity of treated wastewater was assessed using the green alga Pseudokirchneriella subcapitata. Ozonation reduced the toxicity of treated wastewater, while UV irradiation and visible light photocatalysis limited by 20-25% the algal growth due to

  14. The Effect of an Offset Polar Cap Dipolar Magnetic Field on the Modeling of the Vela Pulsar’s γ-Ray Light Curves

    Science.gov (United States)

    Barnard, M.; Venter, C.; Harding, A. K.

    2016-12-01

    We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole B-fields (the latter is characterized by a parameter ɛ), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. The offset-PC dipole B-field mimics deviations from the static dipole (which corresponds to ɛ =0). In addition to constant-emissivity geometric models, we also considered a slot gap (SG) E-field associated with the offset-PC dipole B-field and found that its inclusion leads to qualitatively different light curves. Solving the particle transport equation shows that the particle energy only becomes large enough to yield significant curvature radiation at large altitudes above the stellar surface, given this relatively low E-field. Therefore, particles do not always attain the radiation-reaction limit. Our overall optimal light curve fit is for the retarded vacuum dipole field and OG model, at an inclination angle α ={78}-1+{1^\\circ } and observer angle \\zeta ={69}-1+{2^\\circ }. For this B-field, the TPC model is statistically disfavored compared to the OG model. For the static dipole field, neither model is significantly preferred. We found that smaller values of ɛ are favored for the offset-PC dipole field when assuming constant emissivity, and larger ɛ values favored for variable emissivity, but not significantly so. When multiplying the SG E-field by a factor of 100, we found improved light curve fits, with α and ζ being closer to best fits from independent studies, as well as curvature radiation reaction at lower altitudes.

  15. The Effect of an Offset Polar Cap Dipolar Magnetic Field on the Modeling of the Vela Pulsar's Gamma-Ray Light Curves

    Science.gov (United States)

    Barnard, M.; Venter, C.; Harding, A. K.

    2016-01-01

    We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole B-fields (the latter is characterized by a parameter epsilon), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. The offset-PC dipole B-field mimics deviations from the static dipole (which corresponds to epsilon equals 0). In addition to constant-emissivity geometric models, we also considered a slot gap (SG) E-field associated with the offset-PC dipole B-field and found that its inclusion leads to qualitatively different light curves. Solving the particle transport equation shows that the particle energy only becomes large enough to yield significant curvature radiation at large altitudes above the stellar surface, given this relatively low E-field. Therefore, particles do not always attain the radiation-reaction limit. Our overall optimal light curve fit is for the retarded vacuum dipole field and OG model, at an inclination angle alpha equals 78 plus or minus 1 degree and observer angle zeta equals 69 plus 2 degrees or minus 1 degree. For this B-field, the TPC model is statistically disfavored compared to the OG model. For the static dipole field, neither model is significantly preferred. We found that smaller values of epsilon are favored for the offset-PC dipole field when assuming constant emissivity, and larger epsilon values favored for variable emissivity, but not significantly so. When multiplying the SG E-field by a factor of 100, we found improved light curve fits, with alpha and zeta being closer to best fits from independent studies, as well as curvature radiation reaction at lower altitudes.

  16. Fluorescence polarization measures energy funneling in single light-harvesting antennas--LH2 vs conjugated polymers.

    Science.gov (United States)

    Camacho, Rafael; Tubasum, Sumera; Southall, June; Cogdell, Richard J; Sforazzini, Giuseppe; Anderson, Harry L; Pullerits, Tõnu; Scheblykin, Ivan G

    2015-10-19

    Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ε = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.

  17. Polarized light microscopy reveals physiological and drug-induced changes in surfactant membrane assembly in alveolar type II pneumocytes.

    Science.gov (United States)

    Haller, Thomas; Cerrada, Alejandro; Pfaller, Kristian; Braubach, Peter; Felder, Edward

    2018-01-06

    In alveolar type II (AT II) cells, pulmonary surfactant (PS) is synthetized, stored and exocytosed from lamellar bodies (LBs), specialized large secretory organelles. By applying polarization microscopy (PM), we confirm a specific optical anisotropy of LBs, which indicates a liquid-crystalline mesophase of the stored surfactant phospholipids (PL) and an unusual case of a radiation-symmetric, spherocrystalline organelle. Evidence is shown that the degree of anisotropy is dependent on the amount of lipid layers and their degree of hydration, but unaffected by acutely modulating vital cell parameters like intravesicular pH or cellular energy supply. In contrast, physiological factors that perturb this structure include osmotic cell volume changes and LB exocytosis. In addition, we found two pharmaceuticals, Amiodarone and Ambroxol, both of which severely affect the liquid-crystalline order. Our study shows that PM is an easy, very sensitive, but foremost non-invasive and label-free method able to collect important structural information of PS assembly in live AT II cells which otherwise would be accessible by destructive or labor intense techniques only. This may open new approaches to dynamically investigate LB biosynthesis - the incorporation, folding and packing of lipid membranes - or the initiation of pathological states that manifest in altered LB structures. Due to the observed drug effects, we further suggest that PM provides an appropriate way to study unspecific drug interactions with alveolar cells and even drug-membrane interactions in general. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Fluorescence polarization measures energy funneling in single light-harvesting antennas—LH2 vs conjugated polymers

    Science.gov (United States)

    Camacho, Rafael; Tubasum, Sumera; Southall, June; Cogdell, Richard J.; Sforazzini, Giuseppe; Anderson, Harry L.; Pullerits, Tõnu; Scheblykin, Ivan G.

    2015-10-01

    Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ɛ). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ɛ = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.

  19. Semi-reciprocal polarization maintaining fibre coupler with distinctive transmission characteristics.

    Science.gov (United States)

    Wang, Xinyue; Thomas, Freya; Wang, Ziyu

    2015-11-27

    Optical couplers are very important devices in optical communication systems and optical sensor systems. Several types of optical couplers with different materials or different transmission characteristics have been reported. Here we propose a semi-reciprocal polarization maintaining fibre coupler with unique transmission characteristics, which is distinct from conventional polarization maintaining fibre couplers and polarization beam splitters, and investigate the characteristics of the coupler theoretically and experimentally. The experimental results show that for circularly and elliptically polarized input light, the proposed coupler will act both as an in-line polariser and a conventional polarization maintaining fibre coupler. The output polarization extinction ratio of the transmission arm is 31.79 dB at a centre wavelength of 841 nm. For linearly polarized input light, the coupler will merely act as a conventional 3 dB polarization maintaining fibre coupler. The unique features of the proposed coupler enables the removal of polarisers from optical sensor systems and coherent optical communication systems, and reduces the insertion loss and production cost of the optical path. Therefore there is wide application for this device in optical sensor systems and optical communication systems.

  20. Complex reflection coefficients of p- and s-polarized light at the pseudo-Brewster angle of a dielectric-conductor interface.

    Science.gov (United States)

    Azzam, R M A

    2013-10-01

    The complex Fresnel reflection coefficients r(p) and r(s) of p- and s-polarized light and their ratio ρ=r(p)/r(s) at the pseudo-Brewster angle (PBA) φ(pB) of a dielectric-conductor interface are evaluated for all possible values of the complex relative dielectric function ε=|ε|exp(-jθ)=ε(r)-jε(i), ε(i)>0 that share the same φ(pB). Complex-plane trajectories of r(p), r(s), and ρ at the PBA are presented at discrete values of φ(pB) from 5° to 85° in equal steps of 5° as θ is increased from 0° to 180°. It is shown that for φ(pB)>70° (high-reflectance metals in the IR) r(p) at the PBA is essentially pure negative imaginary and the reflection phase shift δ(p)=arg(r(p))≈-90°. In the domain of fractional optical constants (vacuum UV or light incidence from a high-refractive-index immersion medium) 0reflection phase shifts δ(p), δ(s), Δ=δ(p)-δ(s)=arg(ρ) are also determined as functions of φ(pB).

  1. A review of polarized ion sources

    International Nuclear Information System (INIS)

    Schmor, P.W.

    1995-06-01

    The two main types of polarized ion sources in use on accelerators today are the Atomic Beam Polarized Ion Source (ABIS) source and the Optically Pumped Polarized Ion Source (OPPIS). Both types can provide beams of nuclearly polarized light ions which are either positively or negatively charged. Heavy ion polarized ion sources for accelerators are being developed. (author). 35 refs., 1 tab

  2. Evaluation of the effects of polarized light (λ400-200 nm) on the healing of third-degree burns in induced diabetic and nondiabetic rats.

    Science.gov (United States)

    Oliveira, Priscila Chagas; Pinheiro, Antônio Luiz Barbosa; de Castro, Isabele C V; Reis, João Alves; Noia, Manuela Pimentel; Gurgel, Clarissa; Teixeira Cangussú, Maria Cristina; Pedreira Ramalho, Luciana Maria

    2011-09-01

    The study evaluated, by light microscopy, the repair process on third-degree burns on diabetic and nondiabetic rats, illuminated or not, with a polarized light (PL) source. Burns are severe injuries that result in the loss of fluid and destruction of tissue, infection, and shock that may result in death. Diabetes mellitus is a public health problem that, being uncontrolled, causes severe disturbance to the body metabolism, including on wound healing. PL sources have been shown to be effective in improving healing in many situations. Ninety male Wistar rats were divided into two groups (n=45): nondiabetic and diabetic. In one of the groups, diabetes mellitus was induced by streptozotocin. A third-degree burn, measuring 1.5×1.5 cm(2), was created in the dorsum of each animal. Phototherapy (λ400-2000 nm, 10.2 or 20.4 J/cm(2)) started immediately after burning and was repeated daily until animal death (7, 14, and 21 days). Specimens were taken, processed, and stained with H&E and Sirius red and immunomarked with cytokeratin (CK) AE1/AE3. Descriptive analysis was performed by light microscopy. Animals subjected to phototherapy showed an acceleration of the repair, the dose of 10.2 J/cm(2) being the one that caused best results, including higher deposition of collagen, quicker inflammatory reaction, and improved revascularization. Our results suggest that the use of PL (10.2 J/cm(2)) improves the healing of third-degree burns on both diabetic and nondiabetic animals.

  3. Polarized scintillator targets

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    2000-05-01

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as "live" polarized targets in nuclear physics experiments.

  4. Polarized scintillator targets

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, B. van den E-mail: vandenbrandt@psi.ch; Bunyatova, E.I.; Hautle, P.; Konter, J.A.; Mango, S

    2000-05-21

    The hydrogen nuclei in an organic scintillator have been polarized to more than 80% and the deuterons in its fully deuterated version to 24%. The scintillator, doped with TEMPO, has been polarized dynamically in a field of 2.5 T in a vertical dilution refrigerator in which a plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable solid samples with acceptable optical properties and light output have been prepared and successfully operated as 'live' polarized targets in nuclear physics experiments.

  5. Polarization light curve modelling of corotating interaction regions in the wind of the Wolf-Rayet star WR 6

    Science.gov (United States)

    St-Louis, N.; Tremblay, Patrick; Ignace, Richard

    2018-02-01

    The intriguing WN4b star WR 6 has been known to display epoch-dependent spectroscopic, photometric and polarimetric variability for several decades. In this paper, we set out to verify if a simplified analytical model in which corotating interaction regions (CIRs) threading an otherwise spherical wind is able to reproduce the many broad-band continuum light curves from the literature with a reasonable set of parameters. We modified the optically thin model developed by Ignace, St-Louis & Proulx-Giraldeau to approximately account for multiple scattering and used it to fit 13 separate data sets of this star. By including two CIRs in the wind, we obtained reasonable fits for all data sets with coherent values for the inclination of the rotation axis (i0 = 166°) and for its orientation in the plane of the sky, although in the latter case we obtained two equally acceptable values (ψ = 63° and 152°) from the polarimetry. Additional line profile variation simulations using the Sobolev approximation for the line transfer allowed us to eliminate the ψ = 152° solution. With the adopted configuration (i0 = 166° and ψ = 63°), we were able to reproduce all data sets relatively well with two CIRs located near the stellar equator and always separated by ˜90° in longitude. The epoch dependence comes from the fact that these CIRs migrate along the surface of the star. Density contrasts smaller than a factor of 2 and large opening angles for the CIR (β ⪆ 35°) were found to best reproduce the type of spectroscopic variability reported in the literature.

  6. Linearly and circularly polarized laser photoinduced molecular order in azo dye doped polymer films

    Directory of Open Access Journals (Sweden)

    Saad Bendaoud

    2017-01-01

    Full Text Available Photo-induced behavior of Azo Disperse one (AZD1 doped Poly(Methyl MethAcrylate (PMMA using both linear and circular polarized light is studied. The anisotropy is not erased by the circular polarization light. The circular polarization light combined with relatively long lifetime of the cis state in azo dye doped polymers activate all transverse directions of the angular hole burning through the spot in the film inducing anisotropy. Under circular polarized light, there is no orientation perpendicularly to the helex described by the rotating electric field vector, trans molecules reorients in the propagation direction of the pump beam. The polarization state of the probe beam after propagation through the pumped spot depends strongly on the angle of incidence of both pump and probe beams on the input face. In the case where circular polarized pump and probe beams are under the same angle of incidence, the probe beam “sees” anisotropic film as if it is isotropic. Results of this work shows the possibility to reorient azobenzene-type molecules in two orthogonal directions using alternately linearly and circularly polarized beams.

  7. [Review] Polarization and Polarimetry

    Science.gov (United States)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  8. Simultaneous in situ measurements of properties of particulates in rf silane plasmas using a polarization-sensitive laser-light-scattering method

    Science.gov (United States)

    Shiratani, Masaharu; Kawasaki, Hiroharu; Fukuzawa, Tsuyoshi; Yoshioka, Takashi; Ueda, Yoshio; Singh, Sanjay; Watanabe, Yukio

    1996-01-01

    A polarization-sensitive laser-light-scattering method is developed for simultaneous in situ measurements of properties (size, size dispersion, density, and refractive index) of particulates formed in processing plasmas. The developed system is applied to observe the growth processes of particulates in a range of their size larger than about 10 nm in rf silane plasmas. A size, a size dispersion (logarithm of a standard deviation of size), a density, and a refractive index of particulates in the plasmas are found to be 10-200 nm, about 0.1, 107-109 cm-3 and about 3-5i, respectively. The former three of such values agree fairly well with ones deduced from scanning electron microscopic (SEM) observation. These particulates grow through three phases of nucleation and initial growth, rapid growth, and growth saturation. Coexistence of two size groups of particulates with narrow size dispersions during and after the rapid growth phase verified by the SEM observation may be explained by a model taking into account coagulation between oppositely charged particulates.

  9. Investigation of polarization-induced electric field screening in InGaN light emitting diodes by means of hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Franssen, G.; Suski, T.; Bohdan, R.; Trzeciakowski, W.; Teisseyre, H.; Khachapuridze, A.; Targowski, G.; Krowicki, K.; Czernecki, R. [Institute of High Pressure Physics ' Unipress' , Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw (Poland); Perlin, P.; Leszczynski, M. [Institute of High Pressure Physics ' Unipress' , Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw (Poland); TopGaN Ltd., Sokolowska 29/37, 01-142 Warsaw (Poland); Kurouchi, M.; Nanishi, Y. [Department of Photonics, School of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu, Shiga 525-8577 (Japan); Lu, H.; Schaff, W. [Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York (United States)

    2007-01-15

    We show that the hydrostatic pressure coefficient dE{sub E}/dp of luminescence in In{sub x}Ga{sub 1-x}N epilayers is in the range 20-38 meV/GPa for the entire alloy (0{>=}x{>=}1) and corresponds roughly to the bandgap increase with applied pressure. It is argued that lowering of dE{sub E}/dp in quantum structures of InGaN with respect to this range can be attributed to polarization-induced electric fields (PIEFs). Possible contribution to dE{sub E}/dp originating from In-segregation effects is of secondary importance. This information is used to investigate PIEF screening by free carriers in InGaN-based light emitting diodes (LEDs). We observe that Si doping at a level of 10{sup 19} cm{sup -2} of the barriers in the active region of such LEDs leads to a significant increase of dE {sub E}/dp as compared to LEDs with undoped barriers. This is evidence for efficient screening of PIEFs in the Si-doped devices. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. The use of polarized polychromatic non-coherent light as therapy for acute tennis elbow/lateral epicondylalgia: a pilot study.

    Science.gov (United States)

    Stasinopoulos, Dimitrios

    2005-02-01

    The aim of this study was to assess the efficacy of polarized, polychromatic, non-coherent, low energy light (Bioptron 2, Bioptron AG, Switzerland) in the treatment of acute tennis elbow. Tennis elbow, or lateral epicondylitis, is one of the most common lesions affecting the arm. A plethora of treatment regimes have been described for this condition, but no specific therapy has emerged as a gold standard. A pilot study was carried out with 25 patients who had acute tennis elbow. Bioptron 2 device was applied over lateral epicondyle three times per week for 4 weeks. Pain on VAS, function on VAS, and painfree grip strength were measured at the beginning (week 0) and at the end of the study (week 4). The pain on VAS was reduced at the end of treatment (t(24) = 3.84, p = 0.001). Function on VAS was increased at the end of treatment (t(24) = 4.23, p Bioptron 2 could reduce patients' symptoms with acute tennis elbow, future controlled studies are needed to establish the relative and absolute effectiveness of Bioptron 2.

  11. Bioinspired Polarization Imaging Sensors: From Circuits and Optics to Signal Processing Algorithms and Biomedical Applications: Analysis at the focal plane emulates nature's method in sensors to image and diagnose with polarized light.

    Science.gov (United States)

    York, Timothy; Powell, Samuel B; Gao, Shengkui; Kahan, Lindsey; Charanya, Tauseef; Saha, Debajit; Roberts, Nicholas W; Cronin, Thomas W; Marshall, Justin; Achilefu, Samuel; Lake, Spencer P; Raman, Baranidharan; Gruev, Viktor

    2014-10-01

    In this paper, we present recent work on bioinspired polarization imaging sensors and their applications in biomedicine. In particular, we focus on three different aspects of these sensors. First, we describe the electro-optical challenges in realizing a bioinspired polarization imager, and in particular, we provide a detailed description of a recent low-power complementary metal-oxide-semiconductor (CMOS) polarization imager. Second, we focus on signal processing algorithms tailored for this new class of bioinspired polarization imaging sensors, such as calibration and interpolation. Third, the emergence of these sensors has enabled rapid progress in characterizing polarization signals and environmental parameters in nature, as well as several biomedical areas, such as label-free optical neural recording, dynamic tissue strength analysis, and early diagnosis of flat cancerous lesions in a murine colorectal tumor model. We highlight results obtained from these three areas and discuss future applications for these sensors.

  12. Reprocessing input data validation

    International Nuclear Information System (INIS)

    Persiani, P.J.; Bucher, R.G.; Pond, R.B.; Cornella, R.J.

    1990-01-01

    The Isotope Correlation Technique (ICT), in conjunction with the gravimetric (Pu/U ratio) method for mass determination, provides an independent verification of the input accountancy at the dissolver or accountancy stage of the reprocessing plant. The Isotope Correlation Technique has been applied to many classes of domestic and international reactor systems (light-water, heavy-water, graphite, and liquid-metal) operating in a variety of modes (power, research, production, and breeder), and for a variety of reprocessing fuel cycle management strategies. Analysis of reprocessing operations data based on isotopic correlations derived for assemblies in a PWR environment and fuel management scheme, yielded differences between the measurement-derived and ICT-derived plutonium mass determinations of (-0.02 ± 0.23)% for the measured U-235 and (+0.50 ± 0.31)% for the measured Pu-239, for a core campaign. The ICT analyses has been implemented for the plutonium isotopics in a depleted uranium assembly in a heavy-water, enriched uranium system and for the uranium isotopes in the fuel assemblies in light-water, highly-enriched systems. 7 refs., 5 figs., 4 tabs

  13. Enantiomeric excesses induced in amino acids by ultraviolet circularly polarized light irradiation of extraterrestrial ice analogs: A possible source of asymmetry for prebiotic chemistry

    International Nuclear Information System (INIS)

    Modica, Paola; De Marcellus, Pierre; D'Hendecourt, Louis Le Sergeant; Meinert, Cornelia; Meierhenrich, Uwe J.; Nahon, Laurent

    2014-01-01

    The discovery of meteoritic amino acids with enantiomeric excesses of the L-form (ee L ) has suggested that extraterrestrial organic materials may have contributed to prebiotic chemistry and directed the initial occurrence of the ee L that further led to homochirality of amino acids on Earth. A proposed mechanism for the origin of ee L in meteorites involves an asymmetric photochemistry of extraterrestrial ices by UV circularly polarized light (CPL). We have performed the asymmetric synthesis of amino acids on achiral extraterrestrial ice analogs by VUV CPL, investigating the chiral asymmetry transfer at two different evolutionary stages at which the analogs were irradiated (regular ices and/or organic residues) and at two different photon energies (6.6 and 10.2 eV). We identify 16 distinct amino acids and precisely measure the L-enantiomeric excesses using the enantioselective GC × GC-TOFMS technique in five of them: α-alanine, 2,3-diaminopropionic acid, 2-aminobutyric acid, valine, and norvaline, with values ranging from ee L = –0.20% ± 0.14% to ee L = –2.54% ± 0.28%. The sign of the induced ee L depends on the helicity and the energy of CPL, but not on the evolutionary stage of the samples, and is the same for all five considered amino acids. Our results support an astrophysical scenario in which the solar system was formed in a high-mass star-forming region where icy grains were irradiated during the protoplanetary phase by an external source of CPL of a given helicity and a dominant energy, inducing a stereo-specific photochemistry.

  14. Bare and thin-film-coated substrates with null reflection for p- and s-polarized light at the same angle of incidence: reflectance and ellipsometric parameters as functions of substrate refractive index and film thickness.

    Science.gov (United States)

    Azzam, R M A

    2016-10-20

    Intensity reflectances and ellipsometric parameters of a partially clad transparent substrate that suppresses the reflection of incident p- and s-polarized light at the same angle of incidence from uncoated and single-layer-coated areas are determined as functions of normalized film thickness ς and substrate refractive index n2. The common polarizing angle is the Brewster angle of the ambient-substrate interface, and the light beam incident from the ambient (air or vacuum) is refracted in the film at a 45° angle from the normal to the parallel-plane film boundaries. For n2≤2, the differential reflection phase shift Δ=δp-δs≈±90° for all values of ς so that the Brewster angle is also approximately the principal angle of the film-substrate system independent of film thickness. Accurate techniques for monitoring the deposition of such films are also proposed.

  15. Designing of all optical generalized circuit for two-input binary and multi-valued logical operations

    Science.gov (United States)

    Bhowmik, Panchatapa; Roy, Jitendra Nath; Chattopadhyay, Tanay

    2014-11-01

    This paper presents a generalized all optical circuit of two-input logical operation (both binary and multi-valued), using an optical nonlinear material (OPNLM) based switch. The inputs of the logic gates are represented by different polarization states of light. This model is simple, practical and very much useful for future all optical information processing. Proposed scheme can work for different wavelengths and for different materials. The simulation result with the nonlinear material gold nanoparticle embedded in optically transparent matrices alumina (Al2O3) is also presented in the paper.

  16. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  17. A first-principles study on polar hexagonal Cs2TeM3O12 (M = W, Mo): New visible-light responsive photocatalyst

    Science.gov (United States)

    Zahedi, Ehsan; Hojamberdiev, Mirabbos

    2017-08-01

    The crystal structures, electro-optical properties, and charge carrier effective masses of Cs2TeW3O12 and Cs2TeMo3O12 with hexagonal, polar and non-centrosymmetric crystal structure were investigated based on density functional theory. Cs2TeW3O12 and Cs2TeMo3O12 are found to be indirect K (1/3, 1/3, 0) → G (0, 0, 0) band gap semiconductors (Eg > 3 eV) with small effective masses of photogenerated charge carriers. The mixing of octahedrally coordinated d° transition metal cations (W6+ and Mo6+) with the filled p orbitals of the oxygen ligands leads to the formation of some W5+/Mo5+ sites and splitting of d orbitals into the partially filled t2g (dxy, dyz, and dzx) orbitals and empty eg (dz2 and dx2-y2) orbitals. The top of the valence bond is mainly contributed by O 2p orbital of the oxygen ligands mixed with the partially filled t2g orbitals of W 5d/Mo 4d, while the conduction band mainly consists of empty eg orbitals of W 5d/Mo 4d with a little contribution of O 2p orbitals. The dielectric function exhibits a slight anisotropic behavior and optical absorption peak for Cs2TeW3O12 and Cs2TeMo3O12 belonging to the strong electronic transition O 2p → W 5d/Mo 4d within the octahedral units. According to the estimated valence band and conduction band edges, Cs2TeW3O12 and Cs2TeMo3O12 can be applied as visible-light-responsive photocatalysts for the decomposition of organic pollutants and dye molecules. Also, Cs2TeMo3O12 can be used in water splitting for hydrogen generation but Cs2TeW3O12 requires further experimental studies to confirm its ability for water splitting.

  18. RHIC Polarized proton operation

    International Nuclear Information System (INIS)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J.E.; Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-01-01

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP 4 . A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  19. RHIC Polarized proton operation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D' Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  20. The use of Lorentz group formalism in solving polarization effects of a birefringent single mode optical fiber

    International Nuclear Information System (INIS)

    Ishiekwene, G.C.; Brown, C.S.; Mensah, S.Y.; Bak, A.E.

    2000-07-01

    A theoretical analysis on the polarization effects of a light beam propagating in a birefringent single-mode fiber is presented. We derive a system of differential equations representing the evolution of Stokes parameters and illustrate their application to polarization effects in a straight birefringent single mode optical fiber. The solutions to the set of equations are obtained using specifically the methods of the unified formalism for polarization optics which adopt the use of the Stokes-Mueller equation and the Lorentz group to model polarization phenomena in media such as optical fibers. The analytical results presented using this approach are identical to results obtained from other conventional methods. We observe the characteristic exponential decrease in the total intensity of the input light due to attenuation by the fiber. (author)

  1. Input-output supervisor

    International Nuclear Information System (INIS)

    Dupuy, R.

    1970-01-01

    The input-output supervisor is the program which monitors the flow of informations between core storage and peripheral equipments of a computer. This work is composed of three parts: 1 - Study of a generalized input-output supervisor. With sample modifications it looks like most of input-output supervisors which are running now on computers. 2 - Application of this theory on a magnetic drum. 3 - Hardware requirement for time-sharing. (author) [fr

  2. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  3. Polarized Scintillating Targets at Psi

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.

    2001-02-01

    Scintillating polarized targets are now routinely available: blocks of 18×18×5 mm scintillating organic polymer, doped with TEMPO, polarized dynamically in a field of 2.5 T in a vertical 3He-4He dilution refrigerator. A 19 mm diameter plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat.

  4. Polarization Imaging and Insect Vision

    Science.gov (United States)

    Green, Adam S.; Ohmann, Paul R.; Leininger, Nick E.; Kavanaugh, James A.

    2010-01-01

    For several years we have included discussions about insect vision in the optics units of our introductory physics courses. This topic is a natural extension of demonstrations involving Brewster's reflection and Rayleigh scattering of polarized light because many insects heavily rely on optical polarization for navigation and communication.…

  5. Reduction of the Thomson scattering cross-section in a strong circularly polarized light field in plasma with the change of its spectrum

    Science.gov (United States)

    Korobkin, Vladlen V.; Romanovsky, Michael Y.

    1992-06-01

    It is shown that in a strong circularly polarized laser field, classical electron motion around the ions can occur. The non-relativistic scattering by these electrons in plasma has a certain (Thomson) cross-section only in the limit of a very strong field (it is practically the case of relativistic motion of electrons). In a circularly polarized field with an amplitude on the order of the inneratomic one, the cross section of this process is less. In the spectrum that the scattering of this field gives in plasma, there are non-ion satellites along with the basic frequency.

  6. Role of quantum-confined stark effect on bias dependent photoluminescence of N-polar GaN/InGaN multi-quantum disk amber light emitting diodes

    Science.gov (United States)

    Tangi, Malleswararao; Mishra, Pawan; Janjua, Bilal; Prabaswara, Aditya; Zhao, Chao; Priante, Davide; Min, Jung-Wook; Ng, Tien Khee; Ooi, Boon S.

    2018-03-01

    We study the impact of quantum-confined stark effect (QCSE) on bias dependent micro-photoluminescence emission of the quantum disk (Q-disk) based nanowires light emitting diodes (NWs-LED) exhibiting the amber colored emission. The NWs are found to be nitrogen polar (N-polar) verified using KOH wet chemical etching and valence band spectrum analysis of high-resolution X-ray photoelectron spectroscopy. The crystal structure and quality of the NWs were investigated by high-angle annular dark field - scanning transmission electron microscopy. The LEDs were fabricated to acquire the bias dependent micro-photoluminescence spectra. We observe a redshift and a blueshift of the μPL peak in the forward and reverse bias conditions, respectively, with reference to zero bias, which is in contrast to the metal-polar InGaN well-based LEDs in the literature. Such opposite shifts of μPL peak emission observed for N-polar NWs-LEDs, in our study, are due to the change in the direction of the internal piezoelectric field. The quenching of PL intensity, under the reverse bias conditions, is ascribed to the reduction of electron-hole overlap. Furthermore, the blueshift of μPL emission with increasing excitation power reveals the suppression of QCSE resulting from the photo-generated carriers. Thereby, our study confirms the presence of QCSE for NWs-LEDs from both bias and power dependent μPL measurements. Thus, this study serves to understand the QCSE in N-polar InGaN Q-disk NWs-LEDs and other related wide-bandgap nitride nanowires, in general.

  7. Role of quantum-confined stark effect on bias dependent photoluminescence of N-polar GaN/InGaN multi-quantum disk amber light emitting diodes

    KAUST Repository

    Tangi, Malleswararao

    2018-03-09

    We study the impact of quantum-confined stark effect (QCSE) on bias dependent micro-photoluminescence emission of the quantum disk (Q-disk) based nanowires light emitting diodes (NWs-LED) exhibiting the amber colored emission. The NWs are found to be nitrogen polar (N-polar) verified using KOH wet chemical etching and valence band spectrum analysis of high-resolution X-ray photoelectron spectroscopy. The crystal structure and quality of the NWs were investigated by high-angle annular dark field - scanning transmission electron microscopy. The LEDs were fabricated to acquire the bias dependent micro-photoluminescence spectra. We observe a redshift and a blueshift of the μPL peak in the forward and reverse bias conditions, respectively, with reference to zero bias, which is in contrast to the metal-polar InGaN well-based LEDs in the literature. Such opposite shifts of μPL peak emission observed for N-polar NWs-LEDs, in our study, are due to the change in the direction of the internal piezoelectric field. The quenching of PL intensity, under the reverse bias conditions, is ascribed to the reduction of electron-hole overlap. Furthermore, the blueshift of μPL emission with increasing excitation power reveals the suppression of QCSE resulting from the photo-generated carriers. Thereby, our study confirms the presence of QCSE for NWs-LEDs from both bias and power dependent μPL measurements. Thus, this study serves to understand the QCSE in N-polar InGaN Q-disk NWs-LEDs and other related wide-bandgap nitride nanowires, in general.

  8. Variable Input Power Supply.

    Science.gov (United States)

    An electronic power supply using pulse width modulated (PWM) voltage regulation provides a regulated output for a wide range of input voltages. Thus...switch to change the level of voltage regulation and the turns ratio of the primary winding of the power supply output transformer, thereby obtaining increased tolerance to input voltage change. (Author)

  9. SSYST-2 input description

    International Nuclear Information System (INIS)

    Meyder, R.

    1980-11-01

    The codes system SSYST-2 is designed to analyse the thermal and mechanical behaviour of a fuel rod during a LOCA. The report contains a short introduction into the SSYST structure, a complete input-list for all modules and several tested input-list for a LOCA-analysis. (orig.) [de

  10. MDS MIC Catalog Inputs

    Science.gov (United States)

    Johnson-Throop, Kathy A.; Vowell, C. W.; Smith, Byron; Darcy, Jeannette

    2006-01-01

    This viewgraph presentation reviews the inputs to the MDS Medical Information Communique (MIC) catalog. The purpose of the group is to provide input for updating the MDS MIC Catalog and to request that MMOP assign Action Item to other working groups and FSs to support the MITWG Process for developing MIC-DDs.

  11. Reduction of the Thompson scattering cross section in a strong circularly polarized light field in a plasma with the change of its spectrum. “quantum-classical” electron

    Science.gov (United States)

    Korobkin, V. V.; Romanovsky, M. Yu.

    1992-12-01

    It is shown that in a strong circularly polarized laser field a classical electron motion around ions can occur. The scattering of these electrons in a plasma has the Thompson cross section in the limit of strongs field only and for a subrelativistic motion of the electrons. There are non-ion satellites apart from the basic frequency in the scattering spectrum.

  12. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  13. PLEXOS Input Data Generator

    Energy Technology Data Exchange (ETDEWEB)

    2017-02-01

    The PLEXOS Input Data Generator (PIDG) is a tool that enables PLEXOS users to better version their data, automate data processing, collaborate in developing inputs, and transfer data between different production cost modeling and other power systems analysis software. PIDG can process data that is in a generalized format from multiple input sources, including CSV files, PostgreSQL databases, and PSS/E .raw files and write it to an Excel file that can be imported into PLEXOS with only limited manual intervention.

  14. Berry Phase of Light under Bragg Reflection by Chiral Liquid-Crystal Media.

    Science.gov (United States)

    Barboza, Raouf; Bortolozzo, Umberto; Clerc, Marcel G; Residori, Stefania

    2016-07-29

    A Berry phase is revealed for circularly polarized light when it is Bragg reflected by a chiral liquid-crystal medium of the same handedness. By using a chiral nematic layer we demonstrate that if the input plane of the layer is rotated with respect to a fixed reference frame, a geometric phase effect occurs for the circularly polarized light reflected by the periodic helical structure of the medium. Theory and numerical simulations are supported by an experimental observation, disclosing novel applications in the field of optical manipulation and fundamental optical phenomena.

  15. Dark Polar Dunes

    Science.gov (United States)

    2005-01-01

    20 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, acquired during northern summer in December 2004, shows dark, windblown sand dunes in the north polar region of Mars. A vast sea of sand dunes nearly surrounds the north polar cap. These landforms are located near 80.3oN, 144.1oW. Light-toned features in the image are exposures of the substrate that underlies the dune field. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  16. Polarization, political

    NARCIS (Netherlands)

    Wojcieszak, M.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass

  17. Ultra-thin, single-layer polarization rotator

    Energy Technology Data Exchange (ETDEWEB)

    Son, T. V.; Truong, V. V., E-mail: Truong.Vo-Van@Concordia.Ca [Department of Physics, Concordia University, Montreal, Quebec, H4B 1R6 (Canada); Do, P. A.; Haché, A. [Département de Physique et d’Astronomie, Université de Moncton, Moncton, New Brunswick, E1A 3E9 (Canada)

    2016-08-15

    We demonstrate light polarization control over a broad spectral range by a uniform layer of vanadium dioxide as it undergoes a phase transition from insulator to metal. Changes in refractive indices create unequal phase shifts on s- and p-polarization components of incident light, and rotation of linear polarization shows intensity modulation by a factor of 10{sup 3} when transmitted through polarizers. This makes possible polarization rotation devices as thin as 50 nm that would be activated thermally, optically or electrically.

  18. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  19. Ellipsometry with randomly varying polarization states

    NARCIS (Netherlands)

    Liu, F.; Lee, C. J.; Chen, J. Q.; E. Louis,; van der Slot, P. J. M.; Boller, K. J.; F. Bijkerk,

    2012-01-01

    We show that, under the right conditions, one can make highly accurate polarization-based measurements without knowing the absolute polarization state of the probing light field. It is shown that light, passed through a randomly varying birefringent material has a well-defined orbit on the Poincar

  20. Reflection of circularly polarized light and the effect of particle distribution on circular dichroism in evaporation induced self-assembled cellulose nanocrystal thin films

    Science.gov (United States)

    Hewson, D.; Vukusic, P.; Eichhorn, S. J.

    2017-06-01

    Evaporation induced self-assembled (EISA) thin films of cellulose nanocrystals (CNCs) have shown great potential for displaying structural colour across the visible spectrum. They are believed primarily to reflect left handed circularly polarised (LCP) light due to their natural tendency to form structures comprising left handed chirality. Accordingly the fabrication of homogenously coloured CNC thin films is challenging. Deposition of solid material towards the edge of a dried droplet, via the coffee-stain effect, is one such difficulty in achieving homogenous colour across CNC films. These effects are most easily observed in films prepared from droplets where observable reflection of visible light is localised around the edge of the dry film. We report here, the observation of both left and right hand circularly polarised (LCP/RCP) light in reflection from distinct separate regions of CNC EISA thin films and we elucidate how these reflections are dependent on the distribution of CNC material within the EISA thin film. Optical models of reflection are presented which are based on structures revealed using high resolution transmission electron microscopy (TEM) images of film cross sections. We have also employed spectroscopic characterisation techniques to evaluate the distribution of solid CNC material within a selection of CNC EISA thin films and we have correlated this distribution with polarised light spectra collected from each film. We conclude that film regions from which RCP light was reflected were associated with lower CNC concentrations and thicker film regions.

  1. Reflection of circularly polarized light and the effect of particle distribution on circular dichroism in evaporation induced self-assembled cellulose nanocrystal thin films

    Directory of Open Access Journals (Sweden)

    D. Hewson

    2017-06-01

    Full Text Available Evaporation induced self-assembled (EISA thin films of cellulose nanocrystals (CNCs have shown great potential for displaying structural colour across the visible spectrum. They are believed primarily to reflect left handed circularly polarised (LCP light due to their natural tendency to form structures comprising left handed chirality. Accordingly the fabrication of homogenously coloured CNC thin films is challenging. Deposition of solid material towards the edge of a dried droplet, via the coffee-stain effect, is one such difficulty in achieving homogenous colour across CNC films. These effects are most easily observed in films prepared from droplets where observable reflection of visible light is localised around the edge of the dry film. We report here, the observation of both left and right hand circularly polarised (LCP/RCP light in reflection from distinct separate regions of CNC EISA thin films and we elucidate how these reflections are dependent on the distribution of CNC material within the EISA thin film. Optical models of reflection are presented which are based on structures revealed using high resolution transmission electron microscopy (TEM images of film cross sections. We have also employed spectroscopic characterisation techniques to evaluate the distribution of solid CNC material within a selection of CNC EISA thin films and we have correlated this distribution with polarised light spectra collected from each film. We conclude that film regions from which RCP light was reflected were associated with lower CNC concentrations and thicker film regions.

  2. A Proposal to the Department of Energy for The Fabrication of a Very High Energy Polarized Gama Ray Beam Facility and A Program of Medium Energy Physics Research at The National Synchrotron Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

    1982-09-01

    This proposal requests support for the fabrication and operation of a modest facility that would provide relatively intense beams of monochromatic and polarized photons with energies in the range of several hundreds of MeV. These {gamma} rays would be produced by Compton backscattering laser light from the electrons circulating in the 2.5-3.0 GeV 'X-RAY' storage ring of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The excellent emittance, phase space, and high current of this state-of-the-art storage ring will allow the production of 2 x 10{sup 7} {gamma} rays per second. These photons would be tagged by detecting the scattered electrons, thereby determining the energy to 2.7 MeV for all {gamma}-ray energies. The efficiency of this tagging procedure is 100% and the {gamma}-ray beam would be essentially background free. Tagging will also allow the flexibility of operating with a dynamic range as large as 200 MeV in photon energy while still preserving high resolution and polarization. These beams will permit a fruitful study of important questions in medium-energy nuclear physics. The initial goals of this program are to reach reliable operation with photon energies up to 300 MeV and to develop {gamma}-ray beams with energies up to about 500 MeV. To demonstrate reliable operation, a modest physics program is planned that, for the most part, utilizes existing magnets and detector systems but nonetheless addresses several important outstanding problems. Gamma ray beams of the versatility, intensity, energy, and resolution that can be achieved at this facility are not currently available at any other world facility either existing or under construction. Furthermore, the proposed program would produce the first intense source of medium-energy {gamma} rays that are polarized. Because of the difficulties in producing such polarized beams, it is very unlikely that viable alternate sources can be developed in the near future; at

  3. Polarization states encoded by phase modulation for high bit rate quantum key distribution

    International Nuclear Information System (INIS)

    Liu Xiaobao; Tang Zhilie; Liao Changjun; Lu Yiqun; Zhao Feng; Liu Songhao

    2006-01-01

    We present implementation of quantum cryptography with polarization code by wave-guide type phase modulator. At four different low input voltages of the phase modulator, coder encodes pulses into four different polarization states, 45 o , 135 o linearly polarized or right, left circle polarized, while the decoder serves as the complementary polarizers

  4. ColloInputGenerator

    DEFF Research Database (Denmark)

    2013-01-01

    you to input a text file with a raw list of lexemes that appear in the construction under investigation. This is converted into an a frequency with the format described above. Open this file in a spreadsheet and fill in the corpus-wide word frequencies and save the file as a text file. You can now use...

  5. First correlated measurements of the shape and light scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS probe

    Directory of Open Access Journals (Sweden)

    A. Abdelmonem

    2011-10-01

    Full Text Available Studying the radiative impact of cirrus clouds requires knowledge of the relationship between their microphysics and the single scattering properties of cloud particles. Usually, this relationship is obtained by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS designed to measure simultaneously the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles. Clouds containing particles ranging from a few micrometers to about 800 μm diameter in size can be characterized systematically with an optical resolution power of 2 μm and polar scattering resolution of 1° for forward scattering directions (from 1° to 10° and 8° for side and backscattering directions (from 18° to 170°. The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced size distributions and images comparable to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that modeled using the Ray Tracing with Diffraction on Facets (RTDF program. PHIPS is a highly promising novel airborne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurement instruments.

  6. MARS code manual volume II: input requirements

    International Nuclear Information System (INIS)

    Chung, Bub Dong; Kim, Kyung Doo; Bae, Sung Won; Jeong, Jae Jun; Lee, Seung Wook; Hwang, Moon Kyu

    2010-02-01

    Korea Advanced Energy Research Institute (KAERI) conceived and started the development of MARS code with the main objective of producing a state-of-the-art realistic thermal hydraulic systems analysis code with multi-dimensional analysis capability. MARS achieves this objective by very tightly integrating the one dimensional RELAP5/MOD3 with the multi-dimensional COBRA-TF codes. The method of integration of the two codes is based on the dynamic link library techniques, and the system pressure equation matrices of both codes are implicitly integrated and solved simultaneously. In addition, the Equation-Of-State (EOS) for the light water was unified by replacing the EOS of COBRA-TF by that of the RELAP5. This input manual provides a complete list of input required to run MARS. The manual is divided largely into two parts, namely, the one-dimensional part and the multi-dimensional part. The inputs for auxiliary parts such as minor edit requests and graph formatting inputs are shared by the two parts and as such mixed input is possible. The overall structure of the input is modeled on the structure of the RELAP5 and as such the layout of the manual is very similar to that of the RELAP. This similitude to RELAP5 input is intentional as this input scheme will allow minimum modification between the inputs of RELAP5 and MARS3.1. MARS3.1 development team would like to express its appreciation to the RELAP5 Development Team and the USNRC for making this manual possible

  7. VIIRS/J1 polarization narrative

    Science.gov (United States)

    Waluschka, Eugene; McCorkel, Joel; McIntire, Jeff; Moyer, David; McAndrew, Brendan; Brown, Steven W.; Lykke, Keith R.; Young, James B.; Fest, Eric; Butler, James; Wang, Tung R.; Monroy, Eslim O.; Turpie, Kevin; Meister, Gerhard; Thome, Kurtis J.

    2015-09-01

    The polarization sensitivity of the Visible/NearIR (VISNIR) bands in the Joint Polar Satellite Sensor 1 (J1) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5 %, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4 %, 4.4 %, 3.1 %, and 4.3 %, respectively with a polarization characterization uncertainty of less than 0.38%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands is mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at the National Aeronautics and Space Administration's (NASA) Goddard center and at the National Institute of Science and Technology (NIST) facility and the use of NIST's Traveling Spectral Irradiance and Radiance responsivity Calibrations using Uniform Sources (T-SIRCUS) for polarization testing and associated analyses and results.

  8. VIIRS-J1 Polarization Narrative

    Science.gov (United States)

    Waluschka, Eugene; McCorkel, Joel; McIntire, Jeff; Moyer, David; McAndrew, Brendan; Brown, Steven W.; Lykke, Keith; Butler, James; Meister, Gerhard; Thome, Kurtis J.

    2015-01-01

    The VIS/NIR bands polarization sensitivity of Joint Polar Satellite Sensor 1 (JPSS1) Visible/Infrared Imaging Radiometer Suite (VIIRS) instrument was measured using a broadband source. While polarization sensitivity for bands M5-M7, I1, and I2 was less than 2.5%, the maximum polarization sensitivity for bands M1, M2, M3, and M4 was measured to be 6.4%, 4.4%, 3.1%, and 4.3%, respectively with a polarization characterization uncertainty of less than 0.3%. A detailed polarization model indicated that the large polarization sensitivity observed in the M1 to M4 bands was mainly due to the large polarization sensitivity introduced at the leading and trailing edges of the newly manufactured VISNIR bandpass focal plane filters installed in front of the VISNIR detectors. This was confirmed by polarization measurements of bands M1 and M4 bands using monochromatic light. Discussed are the activities leading up to and including the instruments two polarization tests, some discussion of the polarization model and the model results, the role of the focal plane filters, the polarization testing of the Aft-Optics-Assembly, the testing of the polarizers at Goddard and NIST and the use of NIST's T-SIRCUS for polarization testing and associated analyses and results.

  9. Density and length of stomatal and epidermal cells in "living fossil" trees grown under elevated CO 2 and a polar light regime

    Science.gov (United States)

    Ogaya, R.; Llorens, L.; Peñuelas, J.

    2011-07-01

    During the Cretaceous and early Tertiary, when the climate was warm and the atmospheric CO 2 concentration ([CO 2]) was at least double that of the present-day, polar forests populated high latitude landmasses. We investigated the density and length of stomata and other epidermal cells of two deciduous and three evergreen "living fossil" tree species representative of these ancient forests. These tree species were grown in a simulated Cretaceous high latitude environment at either ambient (400 ppmv) or elevated (800 ppmv) [CO 2] during four years. After 4 years growing at elevated [CO 2], the leaf stomatal density and index (percentage of leaf epidermal cells that are stomata) of these plants were similar to those of their counterparts growing at ambient [CO 2]. While the CO 2 enrichment only modified the stomatal pore length in two of the five studied species, it increased significantly the overall length of the epidermal cells of all the species, reducing their density. These results revealed that leaf epidermal cells of these "living fossil" species were more sensitive than stomata to an experimental doubling of atmospheric CO 2 concentration.

  10. Influence of Solid Target Reflectivity and Incident Angle on Depolarization Ratio and Reflected Energy from Polarized Lights: Experimental Results of the May 2008 Field Trial

    Science.gov (United States)

    2009-11-01

    center No On the list English Name Center x (cm) y (cm) 1 Vive Empty 2 Spectralon blanc White spectralon 25.4 6.75 3 Spectralon noir Black spectralon 44.45...Styrofoam� 26 -22 9 Styro-mousse: noir Black Styrofoam� 41.5 -22 10 Réectik� Reectik� 10 -37.5 11 Styro-mousse noir léger Black light Styrofoam� 26 -37.5...Spectralon blanc White spectralon 25.4 6.75 3 Spectralon noir Black spectralon 44.45 6.75 4 Pins Pine 10 -6.5 5 Épinette Spruce 26 -6.5 6 Merisier Cherry

  11. Political polarization

    OpenAIRE

    Dixit, Avinash K.; Weibull, Jörgen W.

    2007-01-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  12. Political polarization.

    Science.gov (United States)

    Dixit, Avinash K; Weibull, Jörgen W

    2007-05-01

    Failures of government policies often provoke opposite reactions from citizens; some call for a reversal of the policy, whereas others favor its continuation in stronger form. We offer an explanation of such polarization, based on a natural bimodality of preferences in political and economic contexts and consistent with Bayesian rationality.

  13. Carbon nanotube fiber terahertz polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, Ahmed [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Tsentalovich, Dmitri E.; Young, Colin C. [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Heimbeck, Martin S. [Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Everitt, Henry O. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Pasquali, Matteo [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2016-04-04

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼−30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2–1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

  14. Anatomical Reconstruction and Functional Imaging Reveal an Ordered Array of Skylight Polarization Detectors in Drosophila.

    Science.gov (United States)

    Weir, Peter T; Henze, Miriam J; Bleul, Christiane; Baumann-Klausener, Franziska; Labhart, Thomas; Dickinson, Michael H

    2016-05-11

    Many insects exploit skylight polarization as a compass cue for orientation and navigation. In the fruit fly, Drosophila melanogaster, photoreceptors R7 and R8 in the dorsal rim area (DRA) of the compound eye are specialized to detect the electric vector (e-vector) of linearly polarized light. These photoreceptors are arranged in stacked pairs with identical fields of view and spectral sensitivities, but mutually orthogonal microvillar orientations. As in larger flies, we found that the microvillar orientation of the distal photoreceptor R7 changes in a fan-like fashion along the DRA. This anatomical arrangement suggests that the DRA constitutes a detector for skylight polarization, in which different e-vectors maximally excite different positions in the array. To test our hypothesis, we measured responses to polarized light of varying e-vector angles in the terminals of R7/8 cells using genetically encoded calcium indicators. Our data confirm a progression of preferred e-vector angles from anterior to posterior in the DRA, and a strict orthogonality between the e-vector preferences of paired R7/8 cells. We observed decreased activity in photoreceptors in response to flashes of light polarized orthogonally to their preferred e-vector angle, suggesting reciprocal inhibition between photoreceptors in the same medullar column, which may serve to increase polarization contrast. Together, our results indicate that the polarization-vision system relies on a spatial map of preferred e-vector angles at the earliest stage of sensory processing. The fly's visual system is an influential model system for studying neural computation, and much is known about its anatomy, physiology, and development. The circuits underlying motion processing have received the most attention, but researchers are increasingly investigating other functions, such as color perception and object recognition. In this work, we investigate the early neural processing of a somewhat exotic sense, called

  15. GARFEM input deck description

    Energy Technology Data Exchange (ETDEWEB)

    Zdunek, A.; Soederberg, M. (Aeronautical Research Inst. of Sweden, Bromma (Sweden))

    1989-01-01

    The input card deck for the finite element program GARFEM version 3.2 is described in this manual. The program includes, but is not limited to, capabilities to handle the following problems: * Linear bar and beam element structures, * Geometrically non-linear problems (bar and beam), both static and transient dynamic analysis, * Transient response dynamics from a catalog of time varying external forcing function types or input function tables, * Eigenvalue solution (modes and frequencies), * Multi point constraints (MPC) for the modelling of mechanisms and e.g. rigid links. The MPC definition is used only in the geometrically linearized sense, * Beams with disjunct shear axis and neutral axis, * Beams with rigid offset. An interface exist that connects GARFEM with the program GAROS. GAROS is a program for aeroelastic analysis of rotating structures. Since this interface was developed GARFEM now serves as a preprocessor program in place of NASTRAN which was formerly used. Documentation of the methods applied in GARFEM exists but is so far limited to the capacities in existence before the GAROS interface was developed.

  16. Input or intimacy

    Directory of Open Access Journals (Sweden)

    Judit Navracsics

    2014-01-01

    Full Text Available According to the critical period hypothesis, the earlier the acquisition of a second language starts, the better. Owing to the plasticity of the brain, up until a certain age a second language can be acquired successfully according to this view. Early second language learners are commonly said to have an advantage over later ones especially in phonetic/phonological acquisition. Native-like pronunciation is said to be most likely to be achieved by young learners. However, there is evidence of accentfree speech in second languages learnt after puberty as well. Occasionally, on the other hand, a nonnative accent may appear even in early second (or third language acquisition. Cross-linguistic influences are natural in multilingual development, and we would expect the dominant language to have an impact on the weaker one(s. The dominant language is usually the one that provides the largest amount of input for the child. But is it always the amount that counts? Perhaps sometimes other factors, such as emotions, ome into play? In this paper, data obtained from an EnglishPersian-Hungarian trilingual pair of siblings (under age 4 and 3 respectively is analyzed, with a special focus on cross-linguistic influences at the phonetic/phonological levels. It will be shown that beyond the amount of input there are more important factors that trigger interference in multilingual development.

  17. FLUTAN input specifications

    International Nuclear Information System (INIS)

    Borgwaldt, H.; Baumann, W.; Willerding, G.

    1991-05-01

    FLUTAN is a highly vectorized computer code for 3-D fluiddynamic and thermal-hydraulic analyses in cartesian and cylinder coordinates. It is related to the family of COMMIX codes originally developed at Argonne National Laboratory, USA. To a large extent, FLUTAN relies on basic concepts and structures imported from COMMIX-1B and COMMIX-2 which were made available to KfK in the frame of cooperation contracts in the fast reactor safety field. While on the one hand not all features of the original COMMIX versions have been implemented in FLUTAN, the code on the other hand includes some essential innovative options like CRESOR solution algorithm, general 3-dimensional rebalacing scheme for solving the pressure equation, and LECUSSO-QUICK-FRAM techniques suitable for reducing 'numerical diffusion' in both the enthalphy and momentum equations. This report provides users with detailed input instructions, presents formulations of the various model options, and explains by means of comprehensive sample input, how to use the code. (orig.) [de

  18. Structure of polarization-resolved conoscopic patterns of planar oriented liquid crystal cells

    Science.gov (United States)

    Kiselev, A. D.; Vovk, R. G.

    2010-05-01

    The geometry of distributions of the polarization of light in conoscopic patterns of planar oriented nematic and cholesteric liquid crystal (LC) cells is described in terms of the polarization singularities including C-points (points of circular polarization) and L lines (lines of linear polarization). Conditions for the formation of polarization singularities ( C-points) in an ensemble of conoscopic patterns parametrized by the polarization azimuth and ellipticity of the incident light wave have been studied. A characteristic feature of these conditions is selectivity with respect to the polarization parameters of the incident light wave. The polarization azimuth and ellipticity are determining parameters for nematic and cholesteric LC cells, respectively.

  19. Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

    Science.gov (United States)

    Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2017-07-01

    The Polar SWIFT model is a fast scheme for calculating the chemistry of stratospheric ozone depletion in polar winter. It is intended for use in global climate models (GCMs) and Earth system models (ESMs) to enable the simulation of mutual interactions between the ozone layer and climate. To date, climate models often use prescribed ozone fields, since a full stratospheric chemistry scheme is computationally very expensive. Polar SWIFT is based on a set of coupled differential equations, which simulate the polar vortex-averaged mixing ratios of the key species involved in polar ozone depletion on a given vertical level. These species are O3, chemically active chlorine (ClOx), HCl, ClONO2 and HNO3. The only external input parameters that drive the model are the fraction of the polar vortex in sunlight and the fraction of the polar vortex below the temperatures necessary for the formation of polar stratospheric clouds. Here, we present an update of the Polar SWIFT model introducing several improvements over the original model formulation. In particular, the model is now trained on vortex-averaged reaction rates of the ATLAS Chemistry and Transport Model, which enables a detailed look at individual processes and an independent validation of the different parameterizations contained in the differential equations. The training of the original Polar SWIFT model was based on fitting complete model runs to satellite observations and did not allow for this. A revised formulation of the system of differential equations is developed, which closely fits vortex-averaged reaction rates from ATLAS that represent the main chemical processes influencing ozone. In addition, a parameterization for the HNO3 change by denitrification is included. The rates of change of the concentrations of the chemical species of the Polar SWIFT model are purely chemical rates of change in the new version, whereas in the original Polar SWIFT model, they included a transport effect caused by the

  20. Research on generating various polarization-modes in polarized illumination system

    Science.gov (United States)

    Huang, Jinping; Lin, Wumei; Fan, Zhenjie

    2013-08-01

    With the increase of the numerical aperture (NA), the polarization of light affects the imaging quality of projection lens more significantly. On the contrary, according to the mask pattern, the resolution of projection lens can be improved by using the polarized illumination. That is to say, using the corresponding polarized beam (or polarization-mode) along with the off-axis illumination will improve the resolution and the imaging quality of the of projection lens. Therefore, the research on the generation of various polarization modes and its conversion methods become more and more important. In order to realize various polarization modes in polarized illumination system, after read a lot of references, we provide a way that fitting for the illumination system with the wavelength of 193nm.Six polarization-modes and a depolarized mode are probably considered. Wave-plate stack is used to generate linearly polarization-mode, which have a higher degree polarization. In order to generate X-Y and Y-X polarization mode, the equipment consisting of four sectors of λ/2 wave plate was used. We combined 16 sectors of λ/2 wave plate which have different orientations of the "slow" axis to generate radial and azimuthal polarization. Finally, a multi-polarization control device was designed. Using the kind of multi-polarization control device which applying this method could help to choose the polarization modes conveniently and flexibility for the illumination system.

  1. GAROS input deck description

    Energy Technology Data Exchange (ETDEWEB)

    Vollan, A.; Soederberg, M. (Aeronautical Research Inst. of Sweden, Bromma (Sweden))

    1989-01-01

    This report describes the input for the programs GAROS1 and GAROS2, version 5.8 and later, February 1988. The GAROS system, developed by Arne Vollan, Omega GmbH, is used for the analysis of the mechanical and aeroelastic properties for general rotating systems. It has been specially designed to meet the requirements of aeroelastic stability and dynamic response of horizontal axis wind energy converters. Some of the special characteristics are: * The rotor may have one or more blades. * The blades may be rigidly attached to the hub, or they may be fully articulated. * The full elastic properties of the blades, the hub, the machine house and the tower are taken into account. * With the same basic model, a number of different analyses can be performed: Snap-shot analysis, Floquet method, transient response analysis, frequency response analysis etc.

  2. Access to Research Inputs

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Grimpe, Christoph; Pellens, Maikel

    The viability of modern open science norms and practices depend on public disclosure of new knowledge, methods, and materials. However, increasing industry funding of research can restrict the dissemination of results and materials. We show, through a survey sample of 837 German scientists in life...... sciences, natural sciences, engineering, and social sciences, that scientists who receive industry funding are twice as likely to deny requests for research inputs as those who do not. Receiving external funding in general does not affect denying others access. Scientists who receive external funding...... of any kind are, however, 50% more likely to be denied access to research materials by others, but this is not affected by being funded specifically by industry....

  3. Access to Research Inputs

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Grimpe, Christoph; Pellens, Maikel

    2015-01-01

    The viability of modern open science norms and practices depends on public disclosure of new knowledge, methods, and materials. However, increasing industry funding of research can restrict the dissemination of results and materials. We show, through a survey sample of 837 German scientists in life...... sciences, natural sciences, engineering, and social sciences, that scientists who receive industry funding are twice as likely to deny requests for research inputs as those who do not. Receiving external funding in general does not affect denying others access. Scientists who receive external funding...... of any kind are, however, 50 % more likely to be denied access to research materials by others, but this is not affected by being funded specifically by industry...

  4. Polarization methods for diode laser excitation of solid state lasers

    Science.gov (United States)

    Holtom, Gary R.

    2008-11-25

    A mode-locked laser employs a coupled-polarization scheme for efficient longitudinal pumping by reshaped laser diode bars. One or more dielectric polarizers are configured to reflect a pumping wavelength having a first polarization and to reflect a lasing wavelength having a second polarization. A Yb-doped gain medium can be used that absorbs light having a first polarization and emits light having a second polarization. Using such pumping with laser cavity dispersion control, pulse durations of less than 100 fs can be achieved.

  5. Estereoscopia aplicada à neuroanatomia: estudo comparativo entre as técnicas de filtro de cores e de polarização Stereoscopic neuroanatomy: comparative study between anaglyphic and light polarization techniques

    Directory of Open Access Journals (Sweden)

    Murilo Sousa de Meneses

    2002-09-01

    light. Techniques were analyzed for clearness and 3-D effect. Fourteen images were evaluated by 5 people, with scores ranging from 0 to 4. Total mean scores of polarized light was superior compared to the anaglyphic technique. Both methods use the codification of the image, which means separation and exclusivity with each eye seeing its corresponding image. After several photographic essays and gradual adaptation to a better technique, based on optical physics, photography and neuroanatomical knowledge, we concluded that both techniques are suitable means for production of 3-D images. The best technique, however, considering the final quality of image was polarized light, which did not alter the natural color of the specimen, conserving clearness of images with lower cost.

  6. Imaging differential polarization microscope with electronic readout

    International Nuclear Information System (INIS)

    Mickols, W.; Tinoco, I.; Katz, J.E.; Maestre, M.F.; Bustamante, C.

    1985-01-01

    A differential polarization microscope forms two images: one of the transmitted intensity and the other due to the change in intensity between images formed when different polarizations of light are used. The interpretation of these images for linear dichroism and circular dichroism are described. The design constraints on the data acquisition systems and the polarization modulation are described. The advantage of imaging several biological systems which contain optically anisotropic structures are described

  7. PolarTrack: Optical Outside-In Device Tracking that Exploits Display Polarization

    DEFF Research Database (Denmark)

    Rädle, Roman; Jetter, Hans-Christian; Fischer, Jonathan

    2018-01-01

    PolarTrack is a novel camera-based approach to detecting and tracking mobile devices inside the capture volume. In PolarTrack, a polarization filter continuously rotates in front of an off-the-shelf color camera, which causes the displays of observed devices to periodically blink in the camera feed....... The periodic blinking results from the physical characteristics of current displays, which shine polarized light either through an LC overlay to produce images or through a polarizer to reduce light reflections on OLED displays. PolarTrack runs a simple detection algorithm on the camera feed to segment...... tracking accuracy and precision with similar tracking reliability. PolarTrack works as standalone multi-device tracking but is also compatible with existing camera-based tracking systems and can complement them to compensate for their limitations....

  8. Modeling and generating input processes

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.E.

    1987-01-01

    This tutorial paper provides information relevant to the selection and generation of stochastic inputs to simulation studies. The primary area considered is multivariate but much of the philosophy at least is relevant to univariate inputs as well. 14 refs.

  9. Topological events in polarization resolved angular patterns of nematic liquid crystal cells at varying ellipticity of incident wave

    OpenAIRE

    Kiselev, Alexei D.; Vovk, Roman G.

    2008-01-01

    We study the angular structure of polarization of light transmitted through a nematic liquid crystal (NLC) cell by analyzing the polarization state as a function of the incidence angles and the polarization of the incident wave. The polarization resolved angular patterns emerging after the NLC cell illuminated by the convergent light beam are described in terms of the polarization singularities such as C-points (points of circular polarization) and L-lines (lines of linear polarization). For ...

  10. Spontaneous growth of polarizing refractory metal ‘nano-fins’

    Science.gov (United States)

    Tai, M. C.; Gentle, A. R.; Arnold, M. D.; Cortie, M. B.

    2018-03-01

    Traditional polymer polarizers degrade in harsh environments and at high temperatures, reducing the polarization effect. In contrast, polarizers produced with refractory metals have vastly improved thermal stability and resistance to harsh environments but are expensive to fabricate. Here we demonstrate prototype refractory metal wire grid polarizers produced by co-sputtering molybdenum and aluminum under specific conditions. Removal of the aluminum through selective dissolution enables the nanostructure array to transmit light. The polarization spans 500–1100 nm and the extinction ratio significantly increases to >100. Possessing broadband polarization and sufficient extinction ratios, the new polarizing film has potential applications in coatings for sunglasses, windows, pyrometers, scientific instruments, and LCD panels.

  11. Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Hamid Pahlevaninezhad

    2014-09-01

    Full Text Available We present a new fiber-based polarization diversity detection (PDD scheme for polarization sensitive optical coherence tomography (PSOCT. This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM fiber inputs and polarization maintaining (PM fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axes after interference. Advantages of this detection scheme over those with bulk optics PDD include lower cost, easier miniaturization, and more relaxed alignment and handling issues. We incorporate this PDD scheme into a galvanometer-scanned OCT system to demonstrate system calibration and PSOCT imaging of an achromatic quarter-wave plate, fingernail in vivo, and chicken breast, salmon, cow leg, and basa fish muscle samples ex vivo.

  12. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  13. Simulation of Terahertz Frequency Sources. Polar-Optical Phonon Enhancement of Harmonic Generation in Schottky Diodes

    National Research Council Canada - National Science Library

    Gelmont, Boris

    2002-01-01

    ... polar optical vibration frequency When a high frequency input signal is applied to a frequency multiplier device polar-optical phonons can enhance the non-linearities inherent in this device, enabling...

  14. Polarized spatial frequency domain imaging of heart valve fiber structure

    Science.gov (United States)

    Goth, Will; Yang, Bin; Lesicko, John; Allen, Alicia; Sacks, Michael S.; Tunnell, James W.

    2016-03-01

    Our group previously introduced Polarized Spatial Frequency Domain Imaging (PSFDI), a wide-field, reflectance imaging technique which we used to empirically map fiber direction in porcine pulmonary heart valve leaflets (PHVL) without optical clearing or physical sectioning of the sample. Presented is an extended analysis of our PSFDI results using an inverse Mueller matrix model of polarized light scattering that allows additional maps of fiber orientation distribution, along with instrumentation permitting increased imaging speed for dynamic PHVL fiber measurements. We imaged electrospun fiber phantoms with PSFDI, and then compared these measurements to SEM data collected for the same phantoms. PHVL was then imaged and compared to results of the same leaflets optically cleared and imaged with small angle light scattering (SALS). The static PHVL images showed distinct regional variance of fiber orientation distribution, matching our SALS results. We used our improved imaging speed to observe bovine tendon subjected to dynamic loading using a biaxial stretching device. Our dynamic imaging experiment showed trackable changes in the fiber microstructure of biological tissue under loading. Our new PSFDI analysis model and instrumentation allows characterization of fiber structure within heart valve tissues (as validated with SALS measurements), along with imaging of dynamic fiber remodeling. The experimental data will be used as inputs to our constitutive models of PHVL tissue to fully characterize these tissues' elastic behavior, and has immediate application in determining the mechanisms of structural and functional failure in PHVLs used as bio-prosthetic implants.

  15. Serial Input Output

    Energy Technology Data Exchange (ETDEWEB)

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  16. Light-Emitting Pickles

    Science.gov (United States)

    Vollmer, M.; Mollmann, K-P.

    2015-01-01

    We present experiments giving new insights into the classical light-emitting pickle experiment. In particular, measurements of the spectra and temperatures, as well as high-speed recordings, reveal that light emission is connected to the polarity of the electrodes and the presence of hydrogen.

  17. a Spinning Polarizer and Spinning Analyzer Method for Visualizing the Isochromates in Conoscopic Interferometers

    Science.gov (United States)

    Olorunsola, Oluwatobi; Dada, Oluwaseye; Wang, Pengqian

    2013-09-01

    We have developed a spinning polarizer and spinning analyzer (SPSA) method to visualize the whole isochromatic fringes in conoscopic interferometers for the study of optically anisotropic materials. This simple method completely eliminates the broad and dark isogyre fringes appearing in a conventional conoscopic interferometer where a linear polarizer and a linear analyzer (LPLA) are used. Our method allows the direct visualization of the isochromates on the viewing screen by eyes in real time, without the need of additional optics or detectors other than those used in a conventional conoscopic interferometer, and no additional computation is required. This method works at any polarization state of the input light, and at any wavelength permitted by the polarizers. In the case of polychromatic illumination our method reveals the isochromates of all colors indiscriminatively, in comparison to the method of circular polarizer and circular analyzer (CPCA), which is considerably subject to spectrum modulation due to the dispersion in the retardation of the quarter-wave plates. The proposed method is demonstrated in a lithium niobate (LiNbO3) crystal driven by an external electric field.

  18. SDR Input Power Estimation Algorithms

    Science.gov (United States)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  19. Intermediate inputs and economic productivity.

    Science.gov (United States)

    Baptist, Simon; Hepburn, Cameron

    2013-03-13

    Many models of economic growth exclude materials, energy and other intermediate inputs from the production function. Growing environmental pressures and resource prices suggest that this may be increasingly inappropriate. This paper explores the relationship between intermediate input intensity, productivity and national accounts using a panel dataset of manufacturing subsectors in the USA over 47 years. The first contribution is to identify sectoral production functions that incorporate intermediate inputs, while allowing for heterogeneity in both technology and productivity. The second contribution is that the paper finds a negative correlation between intermediate input intensity and total factor productivity (TFP)--sectors that are less intensive in their use of intermediate inputs have higher productivity. This finding is replicated at the firm level. We propose tentative hypotheses to explain this association, but testing and further disaggregation of intermediate inputs is left for further work. Further work could also explore more directly the relationship between material inputs and economic growth--given the high proportion of materials in intermediate inputs, the results in this paper are suggestive of further work on material efficiency. Depending upon the nature of the mechanism linking a reduction in intermediate input intensity to an increase in TFP, the implications could be significant. A third contribution is to suggest that an empirical bias in productivity, as measured in national accounts, may arise due to the exclusion of intermediate inputs. Current conventions of measuring productivity in national accounts may overstate the productivity of resource-intensive sectors relative to other sectors.

  20. Polarized electroluminescence from silicon nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bagraev, Nikolay; Danilovsky, Eduard; Gets, Dmitry; Klyachkin, Leonid; Kudryavtsev, Andrey; Kuzmin, Roman; Malyarenko, Anna [Ioffe Physical-Technical Institute, 194021 St. Petersburg (Russian Federation); Mashkov, Vladimir [St. Petersburg State Polytechnical University, 195251 St. Petersburg (Russian Federation)

    2012-05-15

    We present the first findings of the circularly polarized electroluminescence (CPEL) from silicon nanostructures which are the p-type ultra-narrow silicon quantum well (Si-QW) confined by {delta}-barriers heavily doped with boron. The CPEL dependences on the forward current and lateral electric field show the circularly polarized light emission which appears to be caused by the exciton recombination through the negative-U dipole boron centers at the Si-QW-{delta}-barriers interface with the assistance of phosphorus donors. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. All-fiber polarization switch

    Science.gov (United States)

    Knape, Harald; Margulis, Walter

    2007-03-01

    We report an all-fiber polarization switch made out of silica-based microstructured fiber suitable for Q-switching all-fiber lasers. Nanosecond high-voltage pulses are used to heat and expand an internal electrode to cause λ/2-polarization rotation in less than 10 ns for 1.5 μm light. The 10 cm long component has an experimentally measured optical insertion loss of 0.2 dB and a 0-10 kHz repetition frequency capacity and has been durability tested for more than 109 pulses.

  2. Fiber gyroscope with a double sensitivity employing a polarization splitter.

    Science.gov (United States)

    Zhou, Kejiang; Pan, Shuming; Liu, Shujun; Hu, Keke

    2013-04-15

    An effective method for enhancing the sensitivity of interferometric fiber-optic gyroscope (IFOG) is presented. Light waves propagate twice along the same sensing coil made of polarization-maintaining fiber in different polarization states by inducing a fiber polarization splitter/combining in the IFOG. Preliminary performance data of a gyro prototype exhibits 0.006°/h bias stability.

  3. The research of some polygraphic paper samples's polarization characteristics

    Science.gov (United States)

    Gavryliak, Mykhailo S.; Dobrovolskyi, Yuriy G.; Motrych, Artem V.; Arkhelyuk, Alexander D.

    2018-01-01

    Methods of investigation the polarization characteristics of certain types of polygraph paper were described. The most effective method for estimation of the characteristic features of optical heterogeneities of polygraph paper was proposed. The greatest sensitivity to the structural organization of optical heterogeneities of paper was observed for linearly polarized light beams with 90 degree polarization azimuth.

  4. Precessing deuteron polarization

    International Nuclear Information System (INIS)

    Sitnik, I.M.; Volkov, V.I.; Kirillov, D.A.; Piskunov, N.M.; Plis, Yu.A.

    2002-01-01

    The feasibility of the acceleration in the Nuclotron of deuterons polarized in the horizontal plane is considered. This horizontal polarization is named precessing polarization. The effects of the main magnetic field and synchrotron oscillations are included. The precessing polarization is supposed to be used in studying the polarization parameters of the elastic dp back-scattering and other experiments

  5. Ultra-thin, single-layer polarization rotator

    Directory of Open Access Journals (Sweden)

    T. V. Son

    2016-08-01

    Full Text Available We demonstrate light polarization control over a broad spectral range by a uniform layer of vanadium dioxide as it undergoes a phase transition from insulator to metal. Changes in refractive indices create unequal phase shifts on s- and p-polarization components of incident light, and rotation of linear polarization shows intensity modulation by a factor of 103 when transmitted through polarizers. This makes possible polarization rotation devices as thin as 50 nm that would be activated thermally, optically or electrically.

  6. Diffraction of polarized light on periodic structures

    International Nuclear Information System (INIS)

    Bukanina, V; Divakov, D; Tyutyunnik, A; Hohlov, A

    2012-01-01

    Periodic structures as photonic crystals are widely used in modern laser devices, communication technologies and for creating various beam splitters and filters. Diffraction gratings are applied for creating 3D television sets, DVD and Blu-ray drives and reflective structures (Berkley mirror). It is important to simulate diffraction on such structures to design optical systems with predetermined properties based on photonic crystals and diffraction gratings. Methods of simulating diffraction on periodic structures uses theory of Floquet-Bloch and rigorous coupled-wave analysis (RCWA). Current work is dedicated to analysis of photonic band gaps and simulating diffraction on one-dimensional binary diffraction grating using RCWA. The Maxwell's equations for isotropic media and constitutive relations based on the cgs system were used as a model.

  7. An optically pumped polarized lithium ion source

    International Nuclear Information System (INIS)

    Myers, E.G.; Mendez, A.J.; Schmidt, B.G.; Kemper, K.W.

    1991-01-01

    A laser-optically-pumped polarized lithium ion source is being developed to provide beams of nuclear polarized 6,7 Li - for injection into the FSU tandem Van de Graaff-linac. Electro-optically modulated, circularly polarized light optically pumps a lithium atomic beam into a single magnetic substate, M 1 =1, M J =1/2. No inhomogeneous magnetic field (sextupole or quadrupole) is needed. Adiabatic rf transitions enable the polarization to be changed by transferring the population into different magnetic substates. Using a second electro-optic to modulate a second beam from the same laser, and Zeeman tuning, the polarization of the atomic beam is obtained by laser induced fluorescence. The polarized atomic beam is ionized to Li + and then charge exchanged to Li - . (orig.)

  8. Polare maskuliniteter

    Directory of Open Access Journals (Sweden)

    Marit Anne Hauan

    2012-05-01

    Full Text Available In this paper my aim is to read and understand the journal of Gerrit de Veer from the last journey of William Barents to the Arctic Regions in 1596 and the journal of captain Junge on his hunting trip from Tromsø to Svalbard in 1834.It is nearly 240 years between this to voyages. The first journal is known as the earliest report from the arctic era. Gerrit de Veer adds instructive copper engravings to his text and give us insight in the crews meeting with this new land. Captain Junges journal is found together with his dead crew in a house in a fjord nearby Ny-Ålesund and has no drawings, but word. Both of these journals may be read as sources of the knowledge and understanding of the polar region. They might also unveil the ideas of how to deal with and survive under the challenges that is given. In addition one can ask if the sources can tell us more about how men describe their challenges. Can the way they expressed themselves in the journals give us an understanding of masculinity? And not least help us to create good questions of the change in the ideas of masculinities which is said to follow the change in understanding of the wilderness.

  9. Collective behavior of light in vacuum

    Science.gov (United States)

    Briscese, Fabio

    2018-03-01

    Under the action of light-by-light scattering, light beams show collective behaviors in vacuum. For instance, in the case of two counterpropagating laser beams with specific initial helicity, the polarization of each beam oscillates periodically between the left and right helicity. Furthermore, the amplitudes and the corresponding intensities of each polarization propagate like waves. Such polarization waves might be observationally accessible in future laser experiments, in a physical regime complementary to those explored by particle accelerators.

  10. Light scattering reviews 8 radiative transfer and light scattering

    CERN Document Server

    Kokhanovsky, Alexander A

    2013-01-01

    Light scattering review (vol 8) is aimed at the presentation of recent advances in radiative transfer and light scattering optics. The topics to be covered include: scattering of light by irregularly shaped particles suspended in atmosphere (dust, ice crystals), light scattering by particles much larger as compared the wavelength of incident radiation, atmospheric radiative forcing, astrophysical radiative transfer, radiative transfer and optical imaging in biological media, radiative transfer of polarized light, numerical aspects of radiative transfer.

  11. Polarization-encoded optical shadow-casting logic units: design.

    Science.gov (United States)

    Karim, M A; Awwal, A A; Cherri, A K

    1987-07-15

    A general design algorithm is presented for the multioutput polarization-encoded optical shadow-casting scheme. A set of POSC equations is obtained from the truth table of the desired logic unit and is solved in terms of four possible pixel characteristics (transparent, opaque, vertically polarized, and horizontally polarized) and four possible source characteristics (off, unpolarized, vertically polarized, and horizontally polarized). To demonstrate its feasibility, the algorithm is used to determine the input pixel characteristics of a full adder and a full subtracter.

  12. Switching the response of metasurfaces in polarization standing waves

    OpenAIRE

    Fang, X.; MacDonald, K.F.; Zheludev, N.I.

    2015-01-01

    We demonstrate experimentally that standing waves of polarization, as opposed to intensity, can be engaged to coherently control light-matter interactions in planar photonic nanostructures, presenting unique opportunities for all-optical data processing and polarization-dependent molecular spectroscopy. Such waves, formed by counter-propagating (linear or circular) orthogonally polarized beams can, for example, uniquely detect polarization conversion, planar chirality and related asymmetric t...

  13. Jones matrix treatment for optical Fourier processors with structured polarization.

    Science.gov (United States)

    Moreno, Ignacio; Iemmi, Claudio; Campos, Juan; Yzuel, Maria J

    2011-02-28

    We present a Jones matrix method useful to analyze coherent optical Fourier processors employing structured polarization. The proposed method is a generalization of the standard classical optical Fourier transform processor, but considering vectorial spatial functions with two complex components corresponding to two orthogonal linear polarizations. As a result we derive a Jones matrix that describes the polarization output in terms of two vectorial functions defining respectively the structured polarization input and the generalized polarization impulse response. We apply the method to show and analyze an experiment in which a regular scalar diffraction grating is converted into equivalent polarization diffraction gratings by means of an appropriate polarization filtering. The technique is further demonstrated to generate arbitrary structured polarizations. Excellent experimental results are presented.

  14. Polarization digital holographic microscopy using low-cost liquid crystal polarization rotators

    Science.gov (United States)

    Dovhaliuk, Rostyslav Yu

    2018-02-01

    Polarization imaging methods are actively used to study anisotropic objects. A number of methods and systems, such as imaging polarimeters, were proposed to measure the state of polarization of light that passed through the object. Digital holographic and interferometric approaches can be used to quantitatively measure both amplitude and phase of a wavefront. Using polarization modulation optics, the measurement capabilities of such interference-based systems can be extended to measure polarization-dependent parameters, such as phase retardation. Different kinds of polarization rotators can be used to alternate the polarization of a reference beam. Liquid crystals are used in a rapidly increasing number of different optoelectronic devices. Twisted nematic liquid crystals are widely used as amplitude modulators in electronic displays and light valves or shutter glass. Such devices are of particular interest for polarization imaging, as they can be used as polarization rotators, and due to large-scale manufacturing have relatively low cost. A simple Mach-Zehnder polarized holographic setup that uses modified shutter glass as a polarization rotator is demonstrated. The suggested approach is experimentally validated by measuring retardation of quarter-wave film.

  15. Visualization of polarization state and its application in optics classroom teaching

    Science.gov (United States)

    Lei, Bing; Liu, Wei; Shi, Jianhua; Wang, Wei; Yao, Tianfu; Liu, Shugang

    2017-08-01

    Polarization of light and the related knowledge are key and difficult points in optical teaching, and they are difficult to be understood since they are very abstract concepts. To help students understand the polarization properties of light, some classroom demonstration experiments have been constructed by employing the optical source, polarizers, wave plates optical cage system and polarization axis finder (PAF). The PAF is a polarization indicating device with many linear polarizing components concentric circles, which can visualize the polarization axis's direction of linearly polarized light intuitively. With the help of these demonstration experiment systems, the conversion and difference between the linear polarized light and circularly polarized light have been observed directly by inserting or removing a quarter-wave plate. The rotation phenomenon of linearly polarized light's polarization axis when it propagates through an optical active medium has been observed and studied in experiment, and the strain distribution of some mounted and unmounted lenses have also been demonstrated and observed in experiment conveniently. Furthermore, some typical polarization targets, such as liquid crystal display (LCD), polarized dark glass and skylight, have been observed based on PAF, which is quite suitable to help students understand these targets' polarization properties and the related physical laws. Finally, these demonstration experimental systems have been employed in classroom teaching of our university in physical optics, optoelectronics and photoelectric detection courses, and they are very popular with teachers and students.

  16. Polarization Bremsstrahlung

    CERN Document Server

    Korol, Andrey V

    2014-01-01

    This book introduces and reviews both theory and applications of polarizational bremsstrahlung, i.e. the electromagnetic radiation emitted during collisions of charged particles with structured, thus polarizable targets, such as atoms, molecules and clusters.   The subject, following the first experimental evidence a few decades ago, has gained importance through a number of modern applications.  Thus, the study of several radiative mechanisms is expected to lead to the design of novel light sources, operating in various parts of the electromagnetic spectrum. Conversely, the analysis of the spectral and angular distribution of the photon emission constitutes a new tool for extracting information on the interaction of the colliding particles, and on their internal structure and dynamical properties.   Last but not least, accurate quantitative descriptions of the photon emission processes determine the radiative energy losses of particles in various media, thereby providing essential  information required f...

  17. Polarized light microscopy of hair shafts aids in the differential diagnosis of Chédiak-Higashi and Griscelli-Prunieras syndromes Contribuição do estudo dos cabelos com microscopia de luz polarizada ao diagnóstico diferencial das síndromes de Chédiak-Higashi and Grisceli-Prunieras

    Directory of Open Access Journals (Sweden)

    Neusa Y.S. Valente

    2006-08-01

    Full Text Available PURPOSE: To study and compare the appearance of hairs from patients with Chédiak-Higashi and Griscelli-Prunieras syndromes under light and polarized light microscopy. METHOD: Hairs from 2 Chédiak-Higashi and 2 Griscelli-Prunieras patients were obtained and examined under normal and polarized light microscopy. RESULTS: Under light microscopy, hairs from Chédiak-Higashi patients presented evenly distributed, regular melanin granules, larger than those seen in normal hairs. Under polarized light microscopy, shafts exhibited a bright and polychromatic refringence appearance. In contrast, hair from Griscelli-Prunieras patients, under light microscopy, exhibited bigger and irregular melanin granules, distributed mainly near the medulla. Under polarized light microscopy, shafts appeared monotonously white. CONCLUSION: Light microscopic examination of hair shafts of patients with Chédiak-Higashi or Griscelli-Prunieras syndrome reveals subtle differences that are useful in identifying both disorders, but not in distinguishing between them. We provide evidence that polarized light microscopy of hair shafts, an approach that has not been previously described, aids in differentiating between these syndromes. We propose hair study by polarized light microscopy as a helpful complementary diagnostic method for differential diagnosis between CHS and GPS, especially when the more sophisticated molecular studies are not available.OBJETIVO: Estudar e comparar o aspecto dos cabelos de portadores das síndromes de Chédiak-Higashi e Griscelli-Prunieras, tanto na microscopia óptica convencional quanto com luz polarizada. MÉTODO: Cabelos de dois doentes portadores da síndrome de Chédiak-Higashi e de dois portadores da síndrome de Griscelli-Prunieras foram obtidos e estudados tanto à microscopia convencional quanto com luz polarizada. RESULTADOS: Na microscopia óptica convencional, os cabelos dos doentes portadores da síndrome de Chédiak-Higashi mostraram

  18. Polar heating in Saturn's thermosphere

    Directory of Open Access Journals (Sweden)

    C. G. A. Smith

    2005-10-01

    Full Text Available A 3-D numerical global circulation model of the Kronian thermosphere has been used to investigate the influence of polar heating. The distributions of temperature and winds resulting from a general heat source in the polar regions are described. We show that both the total energy input and its vertical distribution are important to the resulting thermal structure. We find that the form of the topside heating profile is particularly important in determining exospheric temperatures. We compare our results to exospheric temperatures from Voyager occultation measurements (Smith et al., 1983; Festou and Atreya, 1982 and auroral H3+ temperatures from ground-based spectroscopic observations (e.g. Miller et al., 2000. We find that a polar heat source is consistent with both the Smith et al. determination of T∞~400 K at ~30° N and auroral temperatures. The required heat source is also consistent with recent estimates of the Joule heating rate at Saturn (Cowley et al., 2004. However, our results show that a polar heat source can probably not explain the Festou and Atreya determination of T∞~800 K at ~4° N and the auroral temperatures simultaneously. Keywords. Ionosphere (Planetary ionosphere – Magnetospherica physics (Planetary magnetospheres – Meterology and atmospheric dynamics (Thermospheric dynamics

  19. Specular, diffuse and polarized imagery of an oat canopy

    Science.gov (United States)

    Vanderbilt, Vern C.; De Venecia, Kurt J.

    1988-01-01

    Light, polarized by specular reflection, has been found to be an important part of the light scattered by several measured plant canopies. The authors investigate for one canopy the relative importance of specularly reflected sunlight, specularly reflected light from other sources including skylight, and diffusely upwelling light. Polarization images are used to gain increased understanding of the radiation transfer process in a plant canopy. Analysis of the results suggests that properly analyzed polarized remotely sensed data, acquired under specific atmospheric conditions by a specially designed sensor, potentially provide measures of physiological and morphological states of plants in a canopy.

  20. Polarized nuclei in plastic scintillators: a new class of polarized targets

    Science.gov (United States)

    van den Brandt, B.; Bunyatova, E. I.; Hautle, P.; Konter, J. A.; Mango, S.; Nemchonok, I. B.

    2001-06-01

    Polarized scintillating targets are now routinely available: protons, deuterons or other nuclei in blocks of scintillating organic polymer, doped with the free radical TEMPO, are polarized dynamically in a field of 2.5 T in a vertical 3He-4He dilution refrigerator. A 19 mm diameter plastic lightguide transports the scintillation light from the sample in the mixing chamber to a photomultiplier outside the cryostat. Sizeable nuclear polarizations have been achieved newly in boron enriched polystyrene-based scintillating material. A scintillator target with high detection sensitivity for low energy neutrons has been so made available, in which both protons and boron nuclei are polarized. .

  1. Material input of nuclear fuel

    International Nuclear Information System (INIS)

    Rissanen, S.; Tarjanne, R.

    2001-01-01

    The Material Input (MI) of nuclear fuel, expressed in terms of the total amount of natural material needed for manufacturing a product, is examined. The suitability of the MI method for assessing the environmental impacts of fuels is also discussed. Material input is expressed as a Material Input Coefficient (MIC), equalling to the total mass of natural material divided by the mass of the completed product. The material input coefficient is, however, only an intermediate result, which should not be used as such for the comparison of different fuels, because the energy contents of nuclear fuel is about 100 000-fold compared to the energy contents of fossil fuels. As a final result, the material input is expressed in proportion to the amount of generated electricity, which is called MIPS (Material Input Per Service unit). Material input is a simplified and commensurable indicator for the use of natural material, but because it does not take into account the harmfulness of materials or the way how the residual material is processed, it does not alone express the amount of environmental impacts. The examination of the mere amount does not differentiate between for example coal, natural gas or waste rock containing usually just sand. Natural gas is, however, substantially more harmful for the ecosystem than sand. Therefore, other methods should also be used to consider the environmental load of a product. The material input coefficient of nuclear fuel is calculated using data from different types of mines. The calculations are made among other things by using the data of an open pit mine (Key Lake, Canada), an underground mine (McArthur River, Canada) and a by-product mine (Olympic Dam, Australia). Furthermore, the coefficient is calculated for nuclear fuel corresponding to the nuclear fuel supply of Teollisuuden Voima (TVO) company in 2001. Because there is some uncertainty in the initial data, the inaccuracy of the final results can be even 20-50 per cent. The value

  2. Comparison of robust input shapers

    Science.gov (United States)

    Vaughan, Joshua; Yano, Aika; Singhose, William

    2008-09-01

    The rapid movement of machines is a challenging control problem because it often results in high levels of vibration. As a result, flexible machines are typically moved relatively slowly. Input shaping is a control method that allows much higher speeds of motion by limiting vibration induced by the reference command. To design an input-shaping controller, estimates of the system natural frequency and damping ratio are required. However, real world systems cannot be modeled exactly, making the robustness to modeling errors an important consideration. Many robust input shapers have been developed, but robust shapers typically have longer durations that slow the system response. This creates a compromise between shaper robustness and rise time. This paper analyzes the compromise between rapidity of motion and shaper robustness for several input-shaping methods. Experimental results from a portable bridge crane verify the theoretical predictions.

  3. Charge transport in non-polar and semi-polar III-V nitride heterostructures

    International Nuclear Information System (INIS)

    Konar, Aniruddha; Verma, Amit; Fang, Tian; Zhao, Pei; Jana, Raj; Jena, Debdeep

    2012-01-01

    Compared to the intense research focus on the optical properties, the transport properties in non-polar and semi-polar III-nitride semiconductors remain relatively unexplored to date. The purpose of this paper is to discuss charge-transport properties in non-polar and semi-polar orientations of GaN in a comparative fashion to what is known for transport in polar orientations. A comprehensive approach is adopted, starting from an investigation of the differences in the electronic bandstructure along different polar orientations of GaN. The polarization fields along various orientations are then discussed, followed by the low-field electron and hole mobilities. A number of scattering mechanisms that are specific to non-polar and semi-polar GaN heterostructures are identified, and their effects are evaluated. Many of these scattering mechanisms originate due to the coupling of polarization with disorder and defects in various incarnations depending on the crystal orientation. The effect of polarization orientation on carrier injection into quantum-well light-emitting diodes is discussed. This paper ends with a discussion of orientation-dependent high-field charge-transport properties including velocity saturation, instabilities and tunneling transport. Possible open problems and opportunities are also discussed. (paper)

  4. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  5. Basic design of beamline and polarization control

    International Nuclear Information System (INIS)

    Watanabe, M.

    2006-01-01

    The basic concept of synchrotron radiation beamlines for' vacuum ultraviolet and X-ray experiments has been introduced to beginning users and designers of beamlines. The beamline defined here is composed of a front end, pre-mirrors, and a monochromator with refocusing mirrors, which are connected by beam pipes, providing monochromatic light for the experiments. Firstly, time characteristics of the synchrotron radiation are briefly reviewed. Secondly, the basic technology is introduced as the fundamental knowledge required to both users and designers. The topics are photoabsorption by air and solids, front ends and beam pipes, mirrors, monochromators, and filters. Thirdly, the design consideration is described mainly for the designers. The topics are design principle, principle of ray tracing, optical machinery and control, and vacuum. Fourthly, polarization control is considered. The topics are polarizers, polarization diagnosis of beamline, and circularly-polarized light generation. Finally, a brief summary is given introducing some references for further knowledge of the user's and the designers. (authors)

  6. Photonic crystal based polarization insensitive flat lens

    Science.gov (United States)

    Turduev, M.; Bor, E.; Kurt, H.

    2017-07-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a/λ  =  0.280 and a/λ  =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25λ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  7. Polarised light in science and nature

    CERN Document Server

    Pye, J David

    2001-01-01

    We humans cannot see when light is polarized and this leads to unfortunate misapprehensions about this aspect of nature. Even scientists who should know better often assume that it is an obscure topic of specialized interest in only a few rather isolated areas. In fact, it is a universal feature of our world and most natural light is at least partially polarized. In the animal kingdom, insects and other animals exploit such natural polarization in some fascinating ways since they do not share this human deficiency and can both detect and analyze polarization. It may be our unfamiliarity with this aspect of light that also makes people think it is a difficult subject, yet the basis is extremely simple. When these misconceptions are overcome, the phenomena associated with polarization are found to be important throughout science and technology, from physics, astronomy, natural history, geology, chemistry, and several branches of engineering to crafts such as glass-blowing and jewelry. Polarized light also invol...

  8. Unpolarized state of light revisited

    International Nuclear Information System (INIS)

    Prakash, H.; Chandra, N.

    1981-04-01

    The general form of probability distribution function of analytic signal for unpolarized light is found using simple classical arguments. It is shown that the concepts of unpolarized light given in some common standard books are, strictly speaking, not correct. It is proved that if any two orthogonally polarized components of unpolarized light are statistically independent of each other, the light is of chaotic nature. (author)

  9. Demonstration That Calibration of the Instrument Response to Polarizations Parallel and Perpendicular to the Object Space Projected Slit of an Imaging Spectrometer Enable Measurement of the Atmospheric Absorption Spectrum in Region of the Weak CO2 Band for the Case of Arbitrary Polarization: Implication for the Geocarb Mission

    Science.gov (United States)

    Kumer, J. B.; Rairden, R. L.; Polonsky, I. N.; O'Brien, D. M.

    2014-12-01

    The Tropospheric Infrared Mapping Spectrometer (TIMS) unit rebuilt to operate in a narrow spectral region, approximately 1603 to 1615 nm, of the weak CO2 band as described by Kumer et al. (2013, Proc. SPIE 8867, doi:10.1117/12.2022668) was used to conduct the demonstration. An integrating sphere (IS), linear polarizers and quarter wave plate were used to confirm that the instrument's spectral response to unpolarized light, to 45° linearly polarized light and to circular polarized light are identical. In all these cases the intensity components Ip = Is where Ip is the component parallel to the object space projected slit and Is is perpendicular to the slit. In the circular polarized case Ip = Is in the time averaged sense. The polarizer and IS were used to characterize the ratio Rθ of the instrument response to linearly polarized light at the angle θ relative to parallel from the slit, for increments of θ from 0 to 90°, to that of the unpolarized case. Spectra of diffusely reflected sunlight passed through the polarizer in increments of θ, and divided by the respective Rθ showed identical results, within the noise limit, for solar spectrum multiplied by the atmospheric transmission and convolved by the Instrument Line Shape (ILS). These measurements demonstrate that unknown polarization in the diffusely reflected sunlight on this small spectral range affect only the slow change across the narrow band in spectral response relative to that of unpolarized light and NOT the finely structured / high contrast spectral structure of the CO2 atmospheric absorption that is used to retrieve the atmospheric content of CO2. The latter is one of the geoCARB mission objectives (Kumer et al, 2013). The situation is similar for the other three narrow geoCARB bands; O2 A band 757.9 to 768.6 nm; strong CO2 band 2045.0 to 2085.0 nm; CH4 and CO region 2300.6 to 2345.6 nm. Polonsky et al have repeated the mission simulation study doi:10.5194/amt-7-959-2014 assuming no use of a geo

  10. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live......In this paper we estimate the degree, composition and development of geographical income polarization based on data at the individual and municipal level in Denmark from 1984 to 2002. Rising income polarization is reconfirmed when applying new polarization measures, the driving force being greater...

  11. Visible-light photocatalysis in Cu2Se nanowires with exposed {111} facets and charge separation between (111) and (1[combining macron]1[combining macron]1[combining macron]) polar surfaces.

    Science.gov (United States)

    Liu, Bin; Ning, Lichao; Zhao, Hua; Zhang, Congjie; Yang, Heqing; Liu, Shengzhong Frank

    2015-05-28

    The search for active narrow band gap semiconductor photocatalysts that directly split water or degrade organic pollutants under solar irradiation remains an open issue. We synthesized Cu2Se nanowires with exposed {111} facets using ethanol and glycerol as morphology controlling agents. The {111} facets were found to be the active facets for decomposing organic contaminants in the entire solar spectrum. Based on the polar structure of the Cu2Se {111} facets, a charge separation model between polar (111) and (1[combining macron]1[combining macron]1[combining macron]) surfaces is proposed. The internal electric field between polar (111) and (1[combining macron]1[combining macron]1[combining macron]) surfaces created by spontaneous polarization drives charge separation. The reduction and oxidation reactions occur on the positive (111) and negative (1[combining macron]1[combining macron]1[combining macron]) polar surfaces, respectively. This suggests the surface-engineering of narrow band gap semiconductors as a strategy to fabricate photocatalysts with high reactivity in the entire solar spectrum. The charge separation model can deepen the understanding of charge transfer in other semiconductor nanocrystals with high photocatalytic activities and offer guidance to design more effective photocatalysts as well as new types of solar cells, photoelectrodes and photoelectric devices.

  12. The advanced LIGO input optics.

    Science.gov (United States)

    Mueller, Chris L; Arain, Muzammil A; Ciani, Giacomo; DeRosa, Ryan T; Effler, Anamaria; Feldbaum, David; Frolov, Valery V; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J; Kokeyama, Keiko; Korth, William Z; Martin, Rodica M; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H; Tanner, David B; Vorvick, Cheryl; Williams, Luke F; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  13. The advanced LIGO input optics

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Chris L., E-mail: cmueller@phys.ufl.edu; Arain, Muzammil A.; Ciani, Giacomo; Feldbaum, David; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Martin, Rodica M.; Reitze, David H.; Tanner, David B.; Williams, Luke F.; Mueller, Guido [University of Florida, Gainesville, Florida 32611 (United States); DeRosa, Ryan T.; Effler, Anamaria; Kokeyama, Keiko [Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Frolov, Valery V.; Mullavey, Adam [LIGO Livingston Observatory, Livingston, Louisiana 70754 (United States); Kawabe, Keita; Vorvick, Cheryl [LIGO Hanford Observatory, Richland, Washington 99352 (United States); King, Eleanor J. [University of Adelaide, Adelaide, SA 5005 (Australia); and others

    2016-01-15

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  14. Decentralized control with input saturation

    NARCIS (Netherlands)

    Saberi, Ali; Stoorvogel, Antonie Arij; Sannuti, Peddapullaiah

    In decentralized control it is known that the system can be stabilized only if the so-called fixed modes are all stable. If we have input constraints then (semi-)global stability requires all poles to be in the closed left half plane. This paper establishes that these two requirements are necessary

  15. Remote input/output station

    CERN Multimedia

    1972-01-01

    A general view of the remote input/output station installed in building 112 (ISR) and used for submitting jobs to the CDC 6500 and 6600. The card reader on the left and the line printer on the right are operated by programmers on a self-service basis.

  16. World Input-Output Network.

    Directory of Open Access Journals (Sweden)

    Federica Cerina

    Full Text Available Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD is one of the first efforts to construct the global multi-regional input-output (GMRIO tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries.

  17. Parameter setting and input reduction

    NARCIS (Netherlands)

    Evers, A.; van Kampen, N.J.|info:eu-repo/dai/nl/126439737

    2008-01-01

    The language acquisition procedure identifies certain properties of the target grammar before others. The evidence from the input is processed in a stepwise order. Section 1 equates that order and its typical effects with an order of parameter setting. The question is how the acquisition procedure

  18. Topological insulator infrared pseudo-bolometer with polarization sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Peter Anand

    2017-10-25

    Topological insulators can be utilized in a new type of infrared photodetector that is intrinsically sensitive to the polarization of incident light and static magnetic fields. The detector isolates single topological insulator surfaces and allows light collection and exposure to static magnetic fields. The wavelength range of interest is between 750 nm and about 100 microns. This detector eliminates the need for external polarization selective optics. Polarization sensitive infrared photodetectors are useful for optoelectronics applications, such as light detection in environments with low visibility in the visible wavelength regime.

  19. Flat polarization-controlled cylindrical lens based on the Pancharatnam-Berry geometric phase

    Science.gov (United States)

    Piccirillo, Bruno; Florinda Picardi, Michela; Marrucci, Lorenzo; Santamato, Enrico

    2017-05-01

    The working principle of ordinary refractive lenses can be explained in terms of the space-variant optical phase retardations they introduce, which reshape the optical wavefront curvature and hence affect the subsequent light propagation. These phases, in turn, are due to the varying optical path length followed by light at different transverse positions relative to the lens center. A similar lensing behavior can, however, be obtained when the optical phases are introduced by an entirely different mechanism. Here, we consider the ‘geometric phases’ that arise from the polarization transformations occurring in anisotropic optical media, named after Pancharatnam and Berry. The medium anisotropy axis is taken to be space-variant in the transverse plane and the resulting varying geometric phases give rise to the wavefront reshaping and lensing effect, which however also depends on the input polarization. We describe the realization and characterization of a cylindrical geometric-phase lens that is converging for a given input circular-polarization state and diverging for the orthogonal one, which provides one of the simplest possible examples of optical elements based on geometric phases. The demonstrated lens is flat and only a few microns thick (not including the supporting substrates); moreover, its working wavelength can be tuned and the lensing can be switched on and off by the action of an external control electric field. Other kinds of lenses or more general phase elements inducing different wavefront distortions can be obtained by a similar approach. Besides their potential for optoelectronic technology, these devices offer good opportunities for introducing college-level students to an advanced topic of modern physics, such as the Berry phase, with the help of interesting optical demonstrations.

  20. Polarized photon transport through fog

    Science.gov (United States)

    Farmer, Jonathan; Persons, Christopher M.; DeSilva, Robert; Kirkland, James H.; Finney, Greg A.; Fuller, Kirk A.; Hokr, Brett H.

    2017-09-01

    Anyone who has driven through fog understands the detrimental effect scattering can have on your ability to see. When light interacts with a scattering center, in this case a fog droplet, it is scattered into a new direction, ultimately turning the world around you into a dull gray haze. In some fogs, visibility can be less than 100 meters. It would be possible to see through turbid media like fog if you can separate the scattered light from the unscattered, or ballistic, light; however, we must understand the light transport properties of the atmosphere to determine the optimum scheme. Here, we present an end-to-end simulation for polarized light transport through fog. Our approach can be summarized in three steps: compute the Mueller matrix for a single scattering interaction, ensemble average a distribution of sizes and shapes, and solve the light transport using a Monte Carlo simulation. For small spherical particles, such as fog, we use Mie theory to calculate the single scattering Mueller matrix, but this approach can be generalized to non-spherical particles using ray tracing for large particles or a T-matrix approach for smaller particles. Through this simulation, we are able to determine a backscattering Mueller matrix and a forward scattering Mueller matrix response function for the atmosphere as a function of position and detection angle.

  1. Light microscope alignment methods.

    Science.gov (United States)

    Bagnell, Robert

    2014-01-01

    Instructions for proper alignment for each of the most common wide field light microscopy contrast techniques are presented: bright field, polarization, dark field, phase contrast, differential interference contrast, and fluorescence. These are then followed by methods on photomicrography, measurement, and cleaning. An extensive set of Notes provides practical tips for each of these methods.

  2. Polarization-insensitive wavelength conversion of 40 Gb/s NRZ-DPSK signals in a silicon polarization diversity circuit

    DEFF Research Database (Denmark)

    Vukovic, Dragana; Ding, Yunhong; Hu, Hao

    2014-01-01

    Polarization insensitive wavelength conversion of a 40 Gb/s non-return-to-zero (NRZ) differential phase-shift keying (DPSK) data signal is demonstrated using four-wave mixing (FWM) in a silicon nanowire circuit. Polarization independence is achieved using a diversity circuit based on polarization...... rotators and splitters, which is fabricated by a simple process on the silicon-on-insulator (SOI) platform. Error-free performance is achieved with only 0.5 dB of power penalty compared to the wavelength conversion of a signal with well optimized input polarization. Additionally, data transmission over 161...

  3. Front lighted optical tooling method and apparatus

    International Nuclear Information System (INIS)

    Stone, W. J.

    1985-01-01

    An optical tooling method and apparatus uses a front lighted shadowgraphic technique to enhance visual contrast of reflected light. The apparatus includes an optical assembly including a fiducial mark, such as cross hairs, reflecting polarized light with a first polarization, a polarizing element backing the fiducial mark and a reflective surface backing the polarizing element for reflecting polarized light bypassing the fiducial mark and traveling through the polarizing element. The light reflected by the reflecting surface is directed through a second pass of the polarizing element toward the frontal direction with a polarization differing from the polarization of the light reflected by the fiducial mark. When used as a tooling target, the optical assembly may be mounted directly to a reference surface or may be secured in a mounting, such as a magnetic mounting. The optical assembly may also be mounted in a plane defining structure and used as a spherometer in conjunction with an optical depth measuring instrument. A method of measuring a radius of curvature of an unknown surface includes positioning the spherometer on a surface between the surface and a depth measuring optical instrument. As the spherometer is frontally illuminated, the distance from the depth measuring instrument to the fiducial mark and the underlying surface are alternately measured and the difference in these measurements is used as the sagittal height to calculate a radius of curvature

  4. Broadband topology-optimized photonic crystal components for both TE and TM polarizations

    DEFF Research Database (Denmark)

    Têtu, A.; Kristensen, M.; Frandsen, Lars Hagedorn

    2005-01-01

    Several planar photonic crystal components topology-optimized for TE-polarized light, including 60º bends, Y-splitters, and 90º bends, have been characterized for the TM polarization. The experimental results are confirmed by finite-difference time-domain calculations. The surprising efficiency f...... for TM-polarized light is found and paves the way for photonic crystal components suitable for both polarizations....

  5. Polarization Properties of Laser Solitons

    Directory of Open Access Journals (Sweden)

    Pedro Rodriguez

    2017-04-01

    Full Text Available The objective of this paper is to summarize the results obtained for the state of polarization in the emission of a vertical-cavity surface-emitting laser with frequency-selective feedback added. We start our research with the single soliton; this situation presents two perpendicular main orientations, connected by a hysteresis loop. In addition, we also find the formation of a ring-shaped intensity distribution, the vortex state, that shows two homogeneous states of polarization with very close values to those found in the soliton. For both cases above, the study shows the spatially resolved value of the orientation angle. It is important to also remark the appearance of a non-negligible amount of circular light that gives vectorial character to all the different emissions investigated.

  6. Polar cap arcs from the magnetosphere to the ionosphere: kinetic modelling and observations by Cluster and TIMED

    Directory of Open Access Journals (Sweden)

    R. Maggiolo

    2012-02-01

    Full Text Available On 1 April 2004 the GUVI imager onboard the TIMED spacecraft spots an isolated and elongated polar cap arc. About 20 min later, the Cluster satellites detect an isolated upflowing ion beam above the polar cap. Cluster observations show that the ions are accelerated upward by a quasi-stationary electric field. The field-aligned potential drop is estimated to about 700 V and the upflowing ions are accompanied by a tenuous population of isotropic protons with a temperature of about 500 eV. The magnetic footpoints of the ion outflows observed by Cluster are situated in the prolongation of the polar cap arc observed by TIMED GUVI. The upflowing ion beam and the polar cap arc may be different signatures of the same phenomenon, as suggested by a recent statistical study of polar cap ion beams using Cluster data. We use Cluster observations at high altitude as input to a quasi-stationary magnetosphere-ionosphere (MI coupling model. Using a Knight-type current-voltage relationship and the current continuity at the topside ionosphere, the model computes the energy spectrum of precipitating electrons at the top of the ionosphere corresponding to the generator electric field observed by Cluster. The MI coupling model provides a field-aligned potential drop in agreement with Cluster observations of upflowing ions and a spatial scale of the polar cap arc consistent with the optical observations by TIMED. The computed energy spectrum of the precipitating electrons is used as input to the Trans4 ionospheric transport code. This 1-D model, based on Boltzmann's kinetic formalism, takes into account ionospheric processes such as photoionization and electron/proton precipitation, and computes the optical and UV emissions due to precipitating electrons. The emission rates provided by the Trans4 code are compared to the optical observations by TIMED. They are similar in size and intensity. Data and modelling results are consistent with the scenario of quasi

  7. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  8. A cryogenic optical feedthrough using polarization maintaining fibers.

    Science.gov (United States)

    Nelson, M J; Collins, C J; Speake, C C

    2016-03-01

    Polarization maintaining optical fibers can be used to transmit linearly polarized light over long distances but their use in cryogenic environments has been limited by their sensitivity to temperature changes and associated mechanical stress. We investigate experimentally how thermal stresses affect the polarization maintaining fibers and model the observations with Jones matrices. We describe the design, construction, and testing of a feedthrough and fiber termination assembly that uses polarization maintaining fiber to transmit light from a 633 nm HeNe laser at room temperature to a homodyne polarization-based interferometer in a cryogenic vacuum. We report on the efficiency of the polarization maintaining properties of the feedthrough assembly. We also report that, at cryogenic temperatures, the interferometer can achieve a sensitivity of 8 × 10(-10) rad/√Hz at 0.05 Hz using this feedthrough.

  9. Non-coherent continuum scattering as a line polarization mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Del Pino Alemán, T.; Manso Sainz, R.; Trujillo Bueno, J., E-mail: tanausu@iac.es, E-mail: rsainz@iac.es, E-mail: jtb@iac.es [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2014-03-20

    Line scattering polarization can be strongly affected by Rayleigh scattering at neutral hydrogen and Thomson scattering at free electrons. Often a depolarization of the continuum results, but the Doppler redistribution produced by the continuum scatterers, which are light (hence, fast), induces more complex interactions between the polarization in spectral lines and in the continuum. Here we formulate and solve the radiative transfer problem of scattering line polarization with non-coherent continuum scattering consistently. The problem is formulated within the spherical tensor representation of atomic and light polarization. The numerical method of solution is a generalization of the Accelerated Lambda Iteration that is applied to both the atomic system and the radiation field. We show that the redistribution of the spectral line radiation due to the non-coherence of the continuum scattering may modify the shape of the emergent fractional linear polarization patterns significantly, even yielding polarization signals above the continuum level in intrinsically unpolarizable lines.

  10. Polarization attraction using counter-propagating waves in optical fiber at telecommunication wavelengths.

    Science.gov (United States)

    Pitois, S; Fatome, J; Millot, G

    2008-04-28

    In this work, we report the experimental observation of a polarization attraction process which can occur in optical fibers at telecommunication wavelengths. More precisely, we have numerically and experimentally shown that a polarization attractor, based on the injection of two counter-propagating waves around 1.55microm into a 2-m long high nonlinear fiber, can transform any input polarization state into a unique well-defined output polarization state.

  11. An Inexpensive LED Light Sensor

    Science.gov (United States)

    Kutzner, Mickey; Wright, Richard; Kutzner, Emily

    2010-01-01

    Light irradiance measurements are important for students grappling with abstract optical phenomena such as the inverse square law, polarization, diffraction, interference, and spectroscopy. A variety of commercial light sensors are available from scientific vendors such as the CI-6504A from PASCO scientific and the LS-BTA from Vernier Software and…

  12. Polar bears and sea ice habitat change

    Science.gov (United States)

    Durner, George M.; Atwood, Todd C.; Butterworth, Andy

    2017-01-01

    The polar bear (Ursus maritimus) is an obligate apex predator of Arctic sea ice and as such can be affected by climate warming-induced changes in the extent and composition of pack ice and its impacts on their seal prey. Sea ice declines have negatively impacted some polar bear subpopulations through reduced energy input because of loss of hunting habitats, higher energy costs due to greater ice drift, ice fracturing and open water, and ultimately greater challenges to recruit young. Projections made from the output of global climate models suggest that polar bears in peripheral Arctic and sub-Arctic seas will be reduced in numbers or become extirpated by the end of the twenty-first century if the rate of climate warming continues on its present trajectory. The same projections also suggest that polar bears may persist in the high-latitude Arctic where heavy multiyear sea ice that has been typical in that region is being replaced by thinner annual ice. Underlying physical and biological oceanography provides clues as to why polar bear in some regions are negatively impacted, while bears in other regions have shown no apparent changes. However, continued declines in sea ice will eventually challenge the survival of polar bears and efforts to conserve them in all regions of the Arctic.

  13. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  14. Polarization Shaping for Control of Nonlinear Propagation.

    Science.gov (United States)

    Bouchard, Frédéric; Larocque, Hugo; Yao, Alison M; Travis, Christopher; De Leon, Israel; Rubano, Andrea; Karimi, Ebrahim; Oppo, Gian-Luca; Boyd, Robert W

    2016-12-02

    We study the nonlinear optical propagation of two different classes of light beams with space-varying polarization-radially symmetric vector beams and Poincaré beams with lemon and star topologies-in a rubidium vapor cell. Unlike Laguerre-Gauss and other types of beams that quickly experience instabilities, we observe that their propagation is not marked by beam breakup while still exhibiting traits such as nonlinear confinement and self-focusing. Our results suggest that, by tailoring the spatial structure of the polarization, the effects of nonlinear propagation can be effectively controlled. These findings provide a novel approach to transport high-power light beams in nonlinear media with controllable distortions to their spatial structure and polarization properties.

  15. Modelling polarization dependent absorption: The vectorial Lambert-Beer law

    Science.gov (United States)

    Franssens, G.

    2014-07-01

    The scalar Lambert-Beer law, describing the absorption of unpolarized light travelling through a linear non-scattering medium, is simple, well-known, and mathematically trivial. However, when we take the polarization of light into account and consider a medium with polarization dependent absorption, we now need a Vectorial Lambert-Beer Law (VLBL) to quantify this interaction. Such a generalization of the scalar Lambert-Beer law appears not to be readily available. A careful study of this topic reveals that it is not a trivial problem. We will see that the VLBL is not and cannot be a straightforward vectorized version of its scalar counterpart. The aim of the work is to present the general form of the VLBL and to explain how it arises. A reasonable starting point to derive the VLBL is the Vectorial Radiative Transfer Equation (VRTE), which models the absorption and scattering of (partially) polarized light travelling through a linear medium. When we turn off scattering, the VRTE becomes an infinitesimal model for the VLBL holding in the medium. By integrating this equation, we expect to find the VLBL. Surprisingly, this is not the end of the story. It turns out that light propagation through a medium with polarization-dependent absorption is mathematically not that trivial. The trickiness behind the VLBL can be understood in the following terms. The matrix in the VLBL, relating any input Stokes vector to the corresponding output Stokes vector, must necessarily be a Mueller matrix. The subset of invertible Mueller matrices forms a Lie group. It is known that this Lie group contains the ortho-chronous Lorentz group as a subgroup. The group manifold of this subgroup has a (well-known) non-trivial topology. Consequently, the manifold of the Lie group of Mueller matrices also has (at least the same, but likely a more general) non-trivial topology (the full extent of which is not yet known). The type of non-trivial topology, possessed by the manifold of (invertible

  16. Energy conversion evolution at lunar polar sites

    Indian Academy of Sciences (India)

    Lunar polar environments have many advantages from the standpoint of energy supply to robotic and human surface bases.Sunlight is nearly continuous and always horizontal at peaks of perpetual light,while waste heat rejection is aided by the existence of cold,permanently shadowed regions nearby.In this paper a ...

  17. Fluorescence confocal polarizing microscopy: Three-dimensional ...

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  18. Fluorescence confocal polarizing microscopy: Three-dimensional ...

    Indian Academy of Sciences (India)

    Abstract. Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director ...

  19. Polarization sensitive optical coherence tomography detection method

    International Nuclear Information System (INIS)

    Colston, B W; DaSilva, L B; Everett, M J; Featherstone, J D B; Fried, D; Ragadio, J N; Sathyam, U S.

    1999-01-01

    This study demonstrates the potential of polarization sensitive optical coherence tomography (PS-OCT) for non-invasive in vivo detection and characterization of early, incipient caries lesions. PS-OCT generates cross-sectional images of biological tissue while measuring the effect of the tissue on the polarization state of incident light. Clear discrimination between regions of normal and demineralized enamel is first shown in PS-OCT images of bovine enamel blocks containing well-characterized artificial lesions. High-resolution, cross-sectional images of extracted human teeth are then generated that clearly discriminate between the normal and carious regions on both the smooth and occlusal surfaces. Regions of the teeth that appeared to be demineralized in the PS-OCT images were verified using histological thin sections examined under polarized light microscopy. The PS-OCT system discriminates between normal and carious regions by measuring the polarization state of the back-scattered 1310 nm light, which is affected by the state of demineralization of the enamel. Demineralization of enamel increases the scattering coefficient, thus depolarizing the incident light. This study shows that PS-OCT has great potential for the detection, characterization, and monitoring of incipient caries lesions

  20. Fluorescence confocal polarizing microscopy: Three-dimensional ...

    Indian Academy of Sciences (India)

    cholesterics, polarization of both ordinary and extraordinary waves follows the local director (the so-called Mauguin regime) [28]. This effect must be taken into account while interpreting the FCPM images for samples with twist deformations, especially when the twist scale is supra-micron and light propagates along the twist ...

  1. Mars 2.2 code manual: input requirements

    International Nuclear Information System (INIS)

    Chung, Bub Dong; Lee, Won Jae; Jeong, Jae Jun; Lee, Young Jin; Hwang, Moon Kyu; Kim, Kyung Doo; Lee, Seung Wook; Bae, Sung Won

    2003-07-01

    Korea Advanced Energy Research Institute (KAERI) conceived and started the development of MARS code with the main objective of producing a state-of-the-art realistic thermal hydraulic systems analysis code with multi-dimensional analysis capability. MARS achieves this objective by very tightly integrating the one dimensional RELAP5/MOD3 with the multi-dimensional COBRA-TF codes. The method of integration of the two codes is based on the dynamic link library techniques, and the system pressure equation matrices of both codes are implicitly integrated and solved simultaneously. In addition, the Equation-of-State (EOS) for the light water was unified by replacing the EOS of COBRA-TF by that of the RELAP5. This input manual provides a complete list of input required to run MARS. The manual is divided largely into two parts, namely, the one-dimensional part and the multi-dimensional part. The inputs for auxiliary parts such as minor edit requests and graph formatting inputs are shared by the two parts and as such mixed input is possible. The overall structure of the input is modeled on the structure of the RELAP5 and as such the layout of the manual is very similar to that of the RELAP. This similitude to RELAP5 input is intentional as this input scheme will allow minimum modification between the inputs of RELAP5 and MARS. MARS development team would like to express its appreciation to the RELAP5 Development Team and the USNRC for making this manual possible

  2. Electrochemical regulation of budding yeast polarity.

    Directory of Open Access Journals (Sweden)

    Armin Haupt

    2014-12-01

    Full Text Available Cells are naturally surrounded by organized electrical signals in the form of local ion fluxes, membrane potential, and electric fields (EFs at their surface. Although the contribution of electrochemical elements to cell polarity and migration is beginning to be appreciated, underlying mechanisms are not known. Here we show that an exogenous EF can orient cell polarization in budding yeast (Saccharomyces cerevisiae cells, directing the growth of mating projections towards sites of hyperpolarized membrane potential, while directing bud emergence in the opposite direction, towards sites of depolarized potential. Using an optogenetic approach, we demonstrate that a local change in membrane potential triggered by light is sufficient to direct cell polarization. Screens for mutants with altered EF responses identify genes involved in transducing electrochemical signals to the polarity machinery. Membrane potential, which is regulated by the potassium transporter Trk1p, is required for polarity orientation during mating and EF response. Membrane potential may regulate membrane charges through negatively charged phosphatidylserines (PSs, which act to position the Cdc42p-based polarity machinery. These studies thus define an electrochemical pathway that directs the orientation of cell polarization.

  3. Spin polarization of electrons in a magnetic impurity doped ...

    Indian Academy of Sciences (India)

    Abstract. A theoretical model is presented in this paper for degree of spin polarization in a light emitting diode (LED) whose epitaxial region contains quantum dots doped with magnetic impurity. The model is then used to investigate the effect of electron–phonon interaction on degree of spin polarization at different ...

  4. Polarization measurement and vertical aperture optimization for obtaining circularly polarized bend-magnet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Rice, M.; Hussain, Z. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Growing interest in utilizing circular polarization prompted the design of bend-magnet beamline 9.3.2 at the Advanced Light Source, covering the 30-1500 eV spectral region, to include vertical aperturing capabilities for optimizing the collection of circular polarization above and below the orbit plane. After commissioning and early use of the beamline, a multilayer polarimeter was used to characterize the polarization state of the beam as a function of vertical aperture position. This report partially summarizes the polarimetry measurements and compares results with theoretical calculations intended to simulate experimental conditions.

  5. Towards Measurement of Polarization Properties of Skin using the Ellipsometry Technique

    Directory of Open Access Journals (Sweden)

    Pejhman Ghassemi

    2009-03-01

    Full Text Available Introduction: The human skin is an active medium from the optical point of view. Therefore, the diagnostic and therapeutic techniques employing light are increasing. Current optical techniques are based on the measurement of the intensity of reflected absorbed or backscattered light from or within skin. Studies have shown that biological tissues, and in particular skin, demonstrate polarization properties. Scattering of light from the surface of skin or the layers within it is a function of incident polarization. Therefore, by changing the polarization of the incident light and measuring the backscattered light, we can study those skin properties which affect the state of polarization. Material and methods: We have implemented a scattering ellipsometry system in order to investigate the polarization properties of a phantom representing skin. Using the Stocks vector defining the state of polarization and measuring the elements of the Mueller matrix representing the phantom under study, we have shown that by changing the reflection and scattering properties of the sample, polarization characteristics of the backscattered light will be affected. Results: The results of this investigation showed that some elements of the Mueller matrix of the phantom under study were affected by the polarization state of the incident light and the scattering component within the phantom. Therefore, these elements have the potential of being used as polarization markers of the biological tissue. Discussion and conclusion: Upon interaction of polarized light with the skin tissue, the backscattered light will contain optical and polarization information about the skin. Using a simple laboratory-made phantom, we have shown that by analyzing the polarization information within the backscattered light we can study the cause, and possibly the disease, which affected the polarization characteristics of the skin.

  6. Investigation of the polarization state of dual APPLE-II undulators.

    Science.gov (United States)

    Hand, Matthew; Wang, Hongchang; Dhesi, Sarnjeet S; Sawhney, Kawal

    2016-01-01

    The use of an APPLE II undulator is extremely important for providing a high-brilliance X-ray beam with the capability to switch between various photon beam polarization states. A high-precision soft X-ray polarimeter has been used to systematically investigate the polarization characteristics of the two helical APPLE II undulators installed on beamline I06 at Diamond Light Source. A simple data acquisition and processing procedure has been developed to determine the Stokes polarization parameters for light polarized at arbitrary linear angles emitted from a single undulator, and for circularly polarized light emitted from both undulators in conjunction with a single-period undulator phasing unit. The purity of linear polarization is found to deteriorate as the polarization angle moves away from the horizontal and vertical modes. Importantly, a negative correlation between the degree of circular polarization and the photon flux has been found when the phasing unit is used.

  7. Compact LCOS–SLM Based Polarization Pattern Beam Generator

    OpenAIRE

    Zheng, Xuejie; Lizana Tutusaus, Ángel; Peinado, Alba; Ramírez, Claudio; Martínez, Jose L.; Márquez, Andrés; Moreno Soriano, Ignacio; Campos Coloma, Juan

    2015-01-01

    In this paper, a compact optical system for generating arbitrary spatial light polarization patterns is demonstrated. The system uses a single high-resolution liquid crystal (LC) on silicon (LCOS) spatial light modulator. A specialized optical mount is designed and fabricated using a 3D printer, in order to build a compact dual optical architecture, where two different phase patterns are encoded on two adjacent halves of the LCOS screen, with a polarization transformation in between. The fina...

  8. [Fluorescence polarization immunoassay of ractopamine].

    Science.gov (United States)

    Zvereva, E A; Shpakova, N A; Zherdev, A V; Kiu, L; Xu, C; Eremin, S A; Dzantiev, B B

    2016-01-01

    A technique was developed for fluorescence polarization immunoassay (FPIA) of ractopamine, a toxic low molecular weight nonsteroidal growth regulator belonging to the most controlled contaminants of food products of animal origin. The assay is based on the competition between a sample containing ractopamine and ractopamine–fluorophore conjugate for binding to antibodies. The competition is monitored via changes in the degree of fluorescence polarization for plane-polarized excitation light, which differs for the free and antibody-bound forms of the conjugate. The optimal assay conditions were established, ensuring a high accuracy and minimal detection limit. The developed assay demonstrated a detection limit of 1 ng/mL and a range of detectable concentrations of 2.3–50 ng/mL, which met the requirements of sanitary control. The duration of the analysis was 10 min. The possible application of the developed FPIA was demonstrated with testing of turkey meat. The speed and simplicity of the proposed assay define its efficiency as a screening tool for safety of foods.

  9. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  10. Polarization in Sagittarius A*

    OpenAIRE

    Bower, Geoffrey C.

    2000-01-01

    We summarize the current state of polarization observations of Sagittarius A*, the compact radio source and supermassive black hole candidate in the Galactic Center. These observations are providing new tools for understanding accretion disks, jets and their environments. Linear polarization observations have shown that Sgr A* is unpolarized at frequencies as high as 86 GHz. However, recent single-dish observations indicate that Sgr A* may have strong linear polarization at frequencies higher...

  11. Uncertainties of atmospheric polarimetric measurements with sun-sky radiometers induced by errors of relative orientations of polarizers

    Science.gov (United States)

    Li, Li; Li, Zhengqiang; Li, Kaitao; Sun, Bin; Wu, Yanke; Xu, Hua; Xie, Yisong; Goloub, Philippe; Wendisch, Manfred

    2018-04-01

    In this study errors of the relative orientations of polarizers in the Cimel polarized sun-sky radiometers are measured and introduced into the Mueller matrix of the instrument. The linearly polarized light with different polarization directions from 0° to 180° (or 360°) is generated by using a rotating linear polarizer in front of an integrating sphere. Through measuring the referential linearly polarized light, the errors of relative orientations of polarizers are determined. The efficiencies of the polarizers are obtained simultaneously. By taking the error of relative orientation into consideration in the Mueller matrix, the accuracies of the calculated Stokes parameters, the degree of linear polarization, and the angle of polarization are remarkably improved. The method may also apply to other polarization instruments of similar types.

  12. Polarization diverse antenna for dual-band WLAN applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-10-01

    Full Text Available the robustness and capacity of the whole system. Polarization diversity or dual-polarized configurations can assist in realizing bandwidth efficient schemes such as the MIMO-OFDM (Multiple-Input-Multiple- Output – Orthogonal Frequency Division Multiplexing...) scheme, by increasing the system capacity without adding additional antennas at the receiver and transmitter. Various adaptive modulation and demodulation methods have been proposed in conjunction with the OFDM scheme [2] to provide a potentially more...

  13. Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite Polarization Sensitivity Analysis

    Science.gov (United States)

    Sun, Junqiang; Xiong, Xiaoxiong; Waluschka, Eugene; Wang, Menghua

    2016-01-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of five instruments onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite that launched from Vandenberg Air Force Base, California, on October 28, 2011. It is a whiskbroom radiometer that provides +/-56.28deg scans of the Earth view. It has 22 bands, among which 14 are reflective solar bands (RSBs). The RSBs cover a wavelength range from 410 to 2250 nm. The RSBs of a remote sensor are usually sensitive to the polarization of incident light. For VIIRS, it is specified that the polarization factor should be smaller than 3% for 410 and 862 nm bands and 2.5% for other RSBs for the scan angle within +/-45deg. Several polarization sensitivity tests were performed prelaunch for SNPP VIIRS. The first few tests either had large uncertainty or were less reliable, while the last one was believed to provide the more accurate information about the polarization property of the instrument. In this paper, the measured data in the last polarization sensitivity test are analyzed, and the polarization factors and phase angles are derived from the measurements for all the RSBs. The derived polarization factors and phase angles are band, detector, and scan angle dependent. For near-infrared bands, they also depend on the half-angle mirror side. Nevertheless, the derived polarization factors are all within the specification, although the strong detector dependence of the polarization parameters was not expected. Compared to the Moderate Resolution Imaging Spectroradiometer on both Aqua and Terra satellites, the polarization effect on VIIRS RSB is much smaller.

  14. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  15. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

  16. Optical bistability controlling light with light

    CERN Document Server

    Gibbs, Hyatt

    1985-01-01

    Optical Bistability: Controlling Light with Light focuses on optical bistability in nonlinear optical systems. Emphasis is on passive (non-laser) systems that exhibit reversible bistability with input intensity as the hysteresis variable, along with the physics and the potential applications of such systems for nonlinear optical signal processing. This book consists of seven chapters and begins with a historical overview of optical bistability in lasers and passive systems. The next chapter describes steady-state theories of optical bistability, including the Bonifacio-Lugiato model, as we

  17. Giant spin hall effect of light in an exotic optical system

    Science.gov (United States)

    Bag, A.; Chandel, S.; Banerjee, C.; Saha, D.; Pal, M.; Banerjee, A.; Ghosh, N.

    2014-05-01

    We report a giant enhancement of Spin Hall (SH) shift even for normal incidence in an exotic optical system, an inhomogeneous anisotropic medium having complex spatially varying birefringent structure. The spatial variation of birefringence is obtained by changing the three dimensional orientation of liquid crystal by modulating the pixels with user-controlled greyscale value. This polarization dependent spatial variation (in a plane transverse to the direction of propagation of light) of the transmitted light beam (for incident fundamental Gaussian beam lacking any intrinsic angular momentum) through such inhomogeneous anisotropic medium was recorded using an Eigenvalue calibrated Stokes- Mueller imaging system. Giant SH shift was manifested as distinctly different spatial distribution of the recorded output Stokes vector elements for two orthogonal (left and right) input circular polarization states. We unravel the reason for such large enhancement of SH shift by performing rigorous three dimensional analysis of polarization evolution in such complex anisotropic medium. The theoretical analysis revealed that generation of large magnitude of transverse energy flow (quantified via the Poynting vector evolution inside the medium) originating from Spin Orbit Interaction (SOI) in the inhomogeneous birefringent medium leads to the observation of such a large spin dependent deflection of the trajectory of light beam.

  18. Polarization phenomena in quantum chromodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J. [Stanford Univ., CA (United States)

    1994-12-01

    The author discusses a number of interrelated hadronic spin effects which test fundamental features of perturbative and nonperturbative QCD. For example, the anomalous magnetic moment of the proton and the axial coupling g{sub A} on the nucleon are shown to be related to each other for fixed proton radius, independent of the form of the underlying three-quark relativistic quark wavefunction. The renormalization scale and scheme ambiguities for the radiative corrections to the Bjorken sum rule for the polarized structure functions can be eliminated by using commensurate scale relations with other observables. Other examples include (a) new constraints on the shape and normalization of the polarized quark and gluon structure functions of the proton at large and small x{sub bj}; (b) consequences of the principle of hadron retention in high x{sub F} inclusive reactions; (c) applications of hadron helicity conservation to high momentum transfer exclusive reactions; and (d) the dependence of nuclear structure functions and shadowing on virtual photon polarization. The author also discusses the implications of a number of measurements which are in striking conflict with leading-twist perturbative QCD predictions, such as the extraordinarily large spin correlation A{sub NN} observed in large angle proton-proton scattering, the anomalously large {rho}{pi} branching ratio of the J/{psi}, and the rapidly changing polarization dependence of both J/{psi} and continuum lepton pair hadroproduction observed at large x{sub F}. The azimuthal angular dependence of the Drell-Yan process is shown to be highly sensitive to the projectile distribution amplitude, the fundamental valence light-cone wavefunction of the hadron.

  19. Assessment of tissue viability by polarization spectroscopy

    Science.gov (United States)

    Nilsson, G.; Anderson, C.; Henricson, J.; Leahy, M.; O'Doherty, J.; Sjöberg, F.

    2008-09-01

    A new and versatile method for tissue viability imaging based on polarization spectroscopy of blood in superficial tissue structures such as the skin is presented in this paper. Linearly polarized light in the visible wavelength region is partly reflected directly by the skin surface and partly diffusely backscattered from the dermal tissue matrix. Most of the directly reflected light preserves its polarization state while the light returning from the deeper tissue layers is depolarized. By the use of a polarization filter positioned in front of a sensitive CCD-array, the light directly reflected from the tissue surface is blocked, while the depolarized light returning from the deeper tissue layers reaches the detector array. By separating the colour planes of the detected image, spectroscopic information about the amount of red blood cells (RBCs) in the microvascular network of the tissue under investigation can be derived. A theory that utilizes the differences in light absorption of RBCs and bloodless tissue in the red and green wavelength region forms the basis of an algorithm for displaying a colour coded map of the RBC distribution in a tissue. Using a fluid model, a linear relationship (cc. = 0.99) between RBC concentration and the output signal was demonstrated within the physiological range 0-4%. In-vivo evaluation using transepidermal application of acetylcholine by the way of iontophoresis displayed the heterogeneity pattern of the vasodilatation produced by the vasoactive agent. Applications of this novel technology are likely to be found in drug and skin care product development as well as in the assessment of skin irritation and tissue repair processes and even ultimately in a clinic case situation.

  20. Polarization coupling of vector Bessel–Gaussian beams

    International Nuclear Information System (INIS)

    Takeuchi, Ryushi; Kozawa, Yuichi; Sato, Shunichi

    2013-01-01

    We report polarization coupling of radial and azimuthal electric field components of a vector light beam as predicted by the fact that the vector Helmholtz equation is expressed as coupled differential equations in cylindrical coordinates. To clearly observe the polarization variation of a beam as it propagates, higher order transverse modes of a vector Bessel–Gaussian beam were generated by a gain distribution modulation technique, which created a narrow ring-shaped gain region in a Nd:YVO 4 crystal. The polarization coupling was confirmed by the observation that the major polarization component of a vector Bessel–Gaussian beam alternates between radial and azimuthal components along with the propagation. (paper)