WorldWideScience

Sample records for birefringence

  1. Birefringence imaging

    CERN Document Server

    Geday, M A

    2001-01-01

    in tendons. Many transparent materials are optically anisotropic i.e. the refractive index varies with the polarisation orientation of the light. The variation, birefringence, can reveal the underlying anisotropy of the material, whether this anisotropy is caused by the structure of the material or by applied stress. Several methods have been developed to measure the birefringence, although only two imaging microscope techniques, the 'rotating polariser technique' and the 'Polscope', capable of separating the magnitude of the anisotropy (delta or vertical bar sin delta vertical bar), its orientation (phi) and its transmission (l sub 0) are in common use today. In this thesis the rotating polariser technique has been completely revised, with a new and easily accessible user interface as a result. Calibration routines and several analytical tools have been developed. The technique is now capable of measuring the change in birefringence during phase transitions to very high a degree of precision. Examples of the...

  2. Birefringent hollow core fibers

    DEFF Research Database (Denmark)

    Roberts, John

    2007-01-01

    applications, and places emphasis on the development of polarization maintaining (PM) HC-PCF. The polarization cross-coupling characteristics of PM HC-PCF are very different from those of conventional PM fibers. The former fibers have the advantage of suffering far less from stress-field fluctuations, but the......Hollow core photonic crystal fiber (HC-PCF), fabricated according to a nominally non-birefringent design, shows a degree of un-controlled birefringence or polarization mode dispersion far in excess of conventional non polarization maintaining fibers. This can degrade the output pulse in many...... increased overlap between the polarization modes at the glass interfaces. The interplay between these effects leads to a wavelength for optimum polarization maintenance, lambda(PM), which is detuned from the wavelength of highest birefringence. By a suitable fiber design involving antiresonance of the core...

  3. Nonlinear electrodynamics with birefringence

    CERN Document Server

    Kruglov, S I

    2015-01-01

    A new model of nonlinear electrodynamics with three parameters is suggested. The phenomena of vacuum birefringence takes place when there is the external constant magnetic field. We calculate the indices of refraction for two polarizations of electromagnetic waves, parallel and perpendicular to the magnetic induction field. From the Bir\\'{e}fringence Magn\\'{e}tique du Vide (BMV) experiment one of the coefficients, $\\gamma\\approx 10^{-20}$ T$^{-2}$, was estimated. The canonical, symmetrical Belinfante energy-momentum tensors and dilatation current were obtained. The dilatation symmetry and the dual symmetry are broken in the model considered.

  4. A Breather in Birefringent Fibers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The propagation properties of the breather in birefringent fibers are investigated. The breather can propagate stably in strongly birefringent fibers. The propagation law can be expected. However, random birefringence makes the propagation of the breather more complex. The breather will partly disappear and partly appear, even may split into two smaller breathers. In addition, the varying range of relative time displacement between two components of the breather becomes narrower with the effect of third-order dispersion. If third-order dispersion is too strong, the breather behavior will disappear gradually during the transmission. The breather can exist in random birefringent fiber with dispersion management rather than in strongly birefringent fiber.

  5. Birefringence determination in turbid media

    Science.gov (United States)

    Baravian, Christophe; Dillet, Jérôme; Decruppe, Jean-Paul

    2007-03-01

    We study the influence of birefringence on incoherent polarized light transport in turbid media. In particular, Mueller matrices backscattered by a diffusing medium are modified by the birefringence of the suspending phase. We study this effect both theoretically, through Monte Carlo simulations, and experimentally with a highly birefringent xanthane solution in which particles are added at various concentrations to modify its turbidity. Comparisons between experiments on flow-induced birefringence of the xanthane solution with or without particles are in good agreement and show the capability of measuring birefringence in turbid media through analysis of Mueller matrices.

  6. Magnetic birefringence of minerals.

    Science.gov (United States)

    Jennings, Barry R; Wilson, Stephen R; Ridler, Peter J

    2005-01-15

    The earliest reports of magnetically induced optical birefringence included data for liquids, magnetic fluids and colloidal suspensions. Recent work has shown that with relatively straightforward apparatus, when carefully designed and aligned, measurable effects can be recorded even for suspensions of relatively weak diamagnetic materials, including mineral particles. By recording the magnitude of the birefringence induced in magnetic fields of up to two Tesla, a method for the analysis of the magnetic and optical characteristics of these diamagnetic colloids is evidenced. The principles, apparatus and methodology involved are described and novel data reported for the minerals attapulgite, bentonite, hectorite, kaolinite, montmorillonite and vermiculite. Preliminary experiments using pulsed fields on vermiculite sols show that, in favourable circumstances, estimates of particle size can be made by analysing signal response rates. PMID:15571692

  7. Birefringent phononic structures

    Directory of Open Access Journals (Sweden)

    I. E. Psarobas

    2014-12-01

    Full Text Available Within the framework of elastic anisotropy, caused in a phononic crystal due to low crystallographic symmetry, we adopt a model structure, already introduced in the case of photonic metamaterials, and by analogy, we study the effect of birefringence and acoustical activity in a phononic crystal. In particular, we investigate its low-frequency behavior and comment on the factors which determine chirality by reference to this model.

  8. Birefringence phenomena revisited

    CERN Document Server

    Pereira, Dante D; Gonçalves, Bruno

    2016-01-01

    The propagation of electromagnetic waves is investigated in the context of the isotropic and nonlinear dielectric media at rest in the eikonal limit of the geometrical optics. Taking into account the functional dependence $\\varepsilon=\\varepsilon(E,B)$ and $\\mu=\\mu(E,B)$ for the dielectric coefficients, a set of phenomena related to the birefringence of the electromagnetic waves induced by external fields are derived and discussed. Our results contemplate the known cases already reported in the literature: Kerr, Cotton-Mouton, Jones and magnetoelectric effects. Moreover, new effects are presented here as well as the perspectives of its experimental confirmations.

  9. Inflationary Birefringence and Baryogenesis

    CERN Document Server

    Alexander, Stephon H S

    2016-01-01

    A decade ago, the first leptogenesis model based on inflation was proposed, where the complex phase of the inflaton field carries lepton number. If the inflaton field is an axion, it can couple to gravitational waves and gauge fields via. Chern-Simons invariants. Due to these couplings, birefringent gravitational and gauge primordial perturbations are created during inflation to generate a lepton asymmetry, establishing a possible connection between non-vanishing TB-parity violating polarization cross-correlations and leptogenesis. We also discuss the prospect for a subset of these models can directly source circular (V-mode) polarization in the CMB.

  10. Birefringence Measurements on Crystalline Silicon

    CERN Document Server

    Krüger, Christoph; Khalaidovski, Alexander; Steinlechner, Jessica; Nawrodt, Ronny; Schnabel, Roman; Lück, Harald

    2015-01-01

    Crystalline silicon has been proposed as a new test mass material in third generation gravitational wave detectors such as the Einstein Telescope (ET). Birefringence can reduce the interferometric contrast and can produce dynamical disturbances in interferometers. In this work we use the method of polarisation-dependent resonance frequency analysis of Fabry-Perot-cavities containing silicon as a birefringent medium. Our measurements show a birefringence of silicon along the (111) axis of the order of $\\Delta\\, n \\approx 10^{-7}$ at a laser wavelength of 1550nm and room temperature. A model is presented that explains the results of different settings of our measurements as a superposition of elastic strains caused by external stresses in the sample and plastic strains possibly generated during the production process. An application of our theory on the proposed ET test mass geometry suggests no critical effect on birefringence due to elastic strains.

  11. Birefringence measurements on crystalline silicon

    Science.gov (United States)

    Krüger, Christoph; Heinert, Daniel; Khalaidovski, Alexander; Steinlechner, Jessica; Nawrodt, Ronny; Schnabel, Roman; Lück, Harald

    2016-01-01

    Crystalline silicon has been proposed as a new test mass material in third generation gravitational wave detectors such as the Einstein telescope (ET). Birefringence can reduce the interferometric contrast and can produce dynamical disturbances in interferometers. In this work we use the method of polarization-dependent resonance-frequency analysis of Fabry-Perot-cavities containing silicon as a birefringent medium. Our measurements show a birefringence of silicon along the (111) axis of the order of {{Δ }} n≈ {10}-7 at a laser wavelength of 1550 nm and room temperature. A model is presented that explains the results of different settings of our measurements as a superposition of elastic strains caused by external stresses in the sample and plastic strains possibly generated during the production process. An application of our theory on the proposed ET test mass geometry suggests no critical effect on birefringence due to elastic strains.

  12. High-birefringent photonic crystal fiber

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou; Broeng, Jes; Knudsen, Erik;

    2001-01-01

    A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber.......A highly birefringent photonic crystal fiber design is analysed. Birefringence up to 10-3 is found. Random fluctuations in the cladding design are analysed, and the fiber is found to be a feasible polarization maintaining fiber....

  13. Birefringence-induced losses in interferometers

    OpenAIRE

    Winkler, W.; Rüdiger, A.; Schilling, R; Strain, K.; Danzmann, K.

    1994-01-01

    In interferometers one conceivable loss mechanism is depolarization of the light by inherent or thermally induced birefringence in optical substrates or coatings. The magnitude of this effect is determined quantitatively and compared with the losses due to thermal lensing.

  14. Causal Structure and Birefringence in Nonlinear Electrodynamics

    OpenAIRE

    de Melo, C. A. M.; Medeiros, L. G.; Pompeia, P. J.(Instituto de Fomento e Coordenação Industrial, Departamento de Ciência e Tecnologia Aeroespacial, Praça Mal. Eduardo Gomes 50, 12228-901, São José dos Campos, SP , Brazil)

    2014-01-01

    We investigate the causal structure of general nonlinear electrodynamics and determine which Lagrangians generate an effective metric conformal to Minkowski. We also proof that there is only one analytic nonlinear electrodynamics presenting no birefringence.

  15. Polarization conversion loss in birefringent crystalline resonators

    CERN Document Server

    Grudinin, Ivan S; Yu, Nan

    2013-01-01

    Whispering gallery modes in birefringent crystalline resonators are investigated. We experimentally investigate the XY--cut resonators made with LiNbO$_3$, LiTaO$_3$ and BBO and observe strong influence of the resonator's shape and birefringence on the quality factor of the extraordinary polarized modes. We show that extraordinary modes can have lower Q and even be suppressed due to polarization conversion loss. The ordinary ray modes retain the high Q due to inhibited reflection phenomenon.

  16. Novel imaging technique for birefringent materials

    CERN Document Server

    Lewis, J G

    1998-01-01

    less than 40 seconds. Retardation and orientation changes of less than 1nm and 1 deg, respectively, can be resolved with a spatial resolution close to that of a conventional polarizing microscope image. A wide variety of optically anisotropic materials have been examined to demonstrate both the quantitative and qualitative nature of this new sensitive polarization microscopy technique. Preliminary measurements have shown that when the system is extended to use two or more wavelengths it is also capable of directly extracting information about the order of the phase difference. Many transparent materials including crystals, polymers, biological tissues and textile fibres are birefringent or optically anisotropic, i.e. the refractive index varies with the direction of vibration of light. Birefringent measurements are important as they provide information about the underlying structure of a material. In general, the most sensitive techniques for measuring birefringence are those that modulate the polarization st...

  17. Electro-optical tunable birefringent filter

    Energy Technology Data Exchange (ETDEWEB)

    Levinton, Fred M. (Princeton, NJ)

    2012-01-31

    An electrically tunable Lyot type filter is a Lyot that include one or more filter elements. Each filter element may have a planar, solid crystal comprised of a material that exhibits birefringence and is electro-optically active. Transparent electrodes may be coated on each face of the crystal. An input linear light polarizer may be located on one side of the crystal and oriented at 45 degrees to the optical axis of the birefringent crystal. An output linear light polarizer may be located on the other side of the crystal and oriented at -45 degrees with respect to the optical axis of the birefringent crystal. When an electric voltage is applied between the electrodes, the retardation of the crystal changes and so does the spectral transmission of the optical filter.

  18. Ultra-low birefringence dodecagonal vacuum glass cell

    CERN Document Server

    Brakhane, Stefan; Meschede, Dieter; Moon, Geol; Robens, Carsten; Alberti, Andrea

    2015-01-01

    We eport on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence $\\Delta n$ of each window with the cell under vacuum conditions, obtaining values around $\

  19. Astrophysical limits on quantum gravity motivated birefringence

    CERN Document Server

    Gleiser, R J; Gleiser, Reinaldo J.; Kozameh, Carlos N.

    2001-01-01

    We obtain observational upper bounds on a class of quantum gravity related birefringence effects, by analyzing the presence of linear polarization in the optical and ultraviolet spectrum of some distant sources. In the notation of Gambini and Pullin we find $\\chi < 10^{-3}$.

  20. Compact snapshot birefringent imaging Fourier transform spectrometer

    Science.gov (United States)

    Kudenov, Michael W.; Dereniak, Eustace L.

    2010-08-01

    The design and implementation of a compact multiple-image Fourier transform spectrometer (FTS) is presented. Based on the multiple-image FTS originally developed by A. Hirai, the presented device offers significant advantages over his original implementation. Namely, its birefringent nature results in a common-path interferometer which makes the spectrometer insensitive to vibration. Furthermore, it enables the potential of making the instrument ultra-compact, thereby improving the portability of the sensor. The theory of the birefringent FTS is provided, followed by details of its specific embodiment. A laboratory proof of concept of the sensor, designed and developed at the Optical Detection Lab, is also presented. Spectral measurements of laboratory sources are provided, including measurements of light-emitting diodes and gas-discharge lamps. These spectra are verified against a calibrated Ocean Optics USB2000 spectrometer. Other data were collected outdoors, demonstrating the sensor's ability to resolve spectral signatures in standard outdoor lighting and environmental conditions.

  1. Rogue waves in birefringent optical fibers

    CERN Document Server

    Ablowitz, Mark J

    2016-01-01

    Rogue waves in birefringent optical fibers are analyzed within the framework of the coupled nonlinear Schr\\"odinger (CNLS) system. The generation of rogue waves is frequently associated with modulation instability (MI). It is commonly expected that since the CNLS equations exhibit larger growth rates they should also produce more rogue events than their scalar counterparts. This is found to occur only when both equations are focusing. When at least one component is defocusing, the CNLS equations may still exhibit larger growth rates, compared to the scalar system, but that does not necessarily result in more or larger events. The birefringence angle for which the maximum number of events occurs is also identified and the nature of the rogue wave is described for the different cases.

  2. Spectral characterization of nanostructured birefringent porous silicon.

    Science.gov (United States)

    Hakshur, Keren; Yifat, Yuval; Levin, Amit; Ruschin, Shlomo

    2015-12-20

    We present measurements and analysis of the reflection spectrum of white light from a highly birefringent porous silicon layer at different polarization states. We report an anomalous pattern in the spectrum of linearly polarized light at 45° with respect to the principal axes of the layer. This spectrum comprises a combination of two interference effects, namely the Fabry-Perot-type multiple-beam interference present in a simple thin film, and a two-wave interference caused by the beat of two combined orthogonally polarized waves propagating in the birefringent medium. We perform a Fourier analysis of the measured reflected spectra. This analysis furnishes a powerful tool in order to separate the two interference mechanisms and determine the degree of coherence of their superposition. PMID:26837030

  3. Vacuum birefringence in strong inhomogeneous electromagnetic fields

    CERN Document Server

    Karbstein, Felix; Reuter, Maria; Zepf, Matt

    2015-01-01

    Birefringence is one of the fascinating properties of the vacuum of quantum electrodynamics (QED) in strong electromagnetic fields. The scattering of linearly polarized incident probe photons into a perpendicularly polarized mode provides a distinct signature of the optical activity of the quantum vacuum and thus offers an excellent opportunity for a precision test of non-linear QED. Precision tests require accurate predictions and thus a theoretical framework that is capable of taking the detailed experimental geometry into account. We derive analytical solutions for vacuum birefringence which include the spatio-temporal field structure of a strong optical pump laser field and an x-ray probe. We show that the angular distribution of the scattered photons depends strongly on the interaction geometry and find that scattering of the perpendicularly polarized scattered photons out of the cone of the incident probe x-ray beam is the key to making the phenomenon experimentally accessible with the current generatio...

  4. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    Energy Technology Data Exchange (ETDEWEB)

    Della Valle, Federico; Milotti, Edoardo [INFN, Trieste (Italy); Universita di Trieste, Dipt. di Fisica, Trieste (Italy); Ejlli, Aldo; Messineo, Giuseppe; Zavattini, Guido [INFN, Ferrara (Italy); Universita di Ferrara, Dipt. di Fisica e Scienze della Terra, Ferrara (Italy); Gastaldi, Ugo [INFN, Ferrara (Italy); Pengo, Ruggero; Ruoso, Giuseppe [INFN, Lab. Nazionale di Legnaro, Legnaro (Italy)

    2016-01-15

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides a new limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge. (orig.)

  5. Birefringent left-handed metamaterials and perfect lenses

    OpenAIRE

    Zharov, Alexander A.; Zharova, Nina A.; Noskov, Roman E.; Ilya V. Shadrivov; Yuri S. Kivshar

    2004-01-01

    We describe the properties of birefringent left-handed metamaterials and introduce the concept of a birefringent perfect lens. We demonstrate that, in a sharp contrast to the conventional left-handed perfect lens at $\\epsilon=\\mu=-1$, where $\\epsilon$ is the dielectric constant and $\\mu$ is the magnetic permeability, the birefringent left-handed lens can focus either TE or TM polarized waves or both of them, allowing a spatial separation of the TE and TM images. We discuss several application...

  6. X-ray Birefringence in highly Anisotropic Materials

    International Nuclear Information System (INIS)

    Birefringence is the dependence of a material's refractive index on the direction of linear polarization. It induces a phase shift between two perpendicular polarization directions and thus couples linear and circular polarization states. Birefringence in x-ray absorption is as common as linear dichroism but is rarely discussed in the literature. We outline a mathematical framework for describing experiments on birefringence and illustrate the importance of the phenomenon with three examples.

  7. Influence of Photon Mass on Vacuum Birefringence Experiment

    Institute of Scientific and Technical Information of China (English)

    CHEN Min; SHAO Cheng-Gang

    2007-01-01

    Influence of photon mass on vacuum birefringence experiment is analysed according to the nonlinearities of vacuum quantum electrodynamics for the light propagation through an intense electromagnetic field.It is shown that although the photon mass will cause a change of the refractive indices n⊥ and n(‖) of vacuum birefringence,the difference n(‖)-n⊥is unchanged,which means that the effect of photon mass cannot be observed in vacuum birefringence experiment.

  8. Highly birefringent index-guiding photonic crystal fibers

    DEFF Research Database (Denmark)

    Hansen, Theis Peter; Broeng, Jes; Libori, Stig E. Barkou;

    2001-01-01

    . While extremely high degrees of birefringence may be obtained for the fibers, we demonstrate that careful design with respect to multimode behavior must be performed. We further discuss the cutoff properties of birefringent PCFs and present experimental results in agreement with theoretical predictions......Photonic crystal fibers (PCFs) offer new possibilities of realizing highly birefringent fibers due to a higher intrinsic index contrast compared to conventional fibers. In this letter, we analyze theoretically the levels of birefringence that can be expected using relatively simple PCF designs...

  9. Synthesis and Applications of Birefringent Metasurfaces

    CERN Document Server

    Achouri, Karim; Caloz, Christophe

    2016-01-01

    Birefringent metasurfaces are two-dimensional structures capable of independently controlling the amplitude, phase and polarization of orthogonally polarized incident waves. In this work, we propose a in-depth discussion on the mathematical synthesis of such metasurfaces. We compare two methods, one that is rigorous and based on the exact electromagnetic fields involved in the transformation and one that is based on approximate reflection and transmission coefficients. We next validate the synthesis technique in metasurfaces performing the operations of half- and quarter-wave plates, polarization beam splitting and orbital angular momentum multiplexing.

  10. Electric birefringence spectroscopy of montmorillonite particles.

    Science.gov (United States)

    Arenas-Guerrero, Paloma; Iglesias, Guillermo R; Delgado, Ángel V; Jiménez, María L

    2016-06-14

    Electric birefringence (EB) of suspensions of anisotropic particles can be considered an electrokinetic phenomenon in a wide sense, as both liquid motions and polarization of the electrical double layer (EDL) of the particles participate in the process of particle orientation under the applied field. The EB spectrum can be exploited for obtaining information on the dimensions, average value and anisotropy of the surface conductivity of the particles, and the concentration and Maxwell-Wagner polarization of the EDLs. It is thus a highly informative technique, applicable to non-spherical particles. In this paper, we investigate the birefringent response of plate-like montmorillonite particles as a function of the frequency and amplitude of the applied AC electric field, for different compositions (pH, ionic strength, particle concentration) of the suspensions. The transient electric birefringence (i.e., the decay of the refractive index anisotropy with time when the field is switched off) is used for estimating the average dimensions of the particle axes, by modeling it as an oblate spheroid. The obtained values are very similar to those deduced from electron microscopy determinations. The frequency spectra show a very distinct behaviour at low (on the order of a few Hz) and high (up to several MHz) frequencies: the α and Maxwell-Wagner-O'Konski relaxations, characteristic of EDLs, are detected at frequencies above 10 kHz, and they can be well explained using electrokinetic models for the polarization of EDLs. At low frequencies, in contrast, the birefringence changes to negative, an anomalous response meaning that the particles tend to orient with their symmetry axis parallel to the field. This anomaly is weaker at basic pH values, high ionic strengths and low concentrations. The results can be explained by considering the polydispersity of real samples: the fastest particles redistribute around the slowest ones, inducing a hydrodynamic torque opposite to that of

  11. Birefringent thin films and polarizing elements

    CERN Document Server

    Hodgkinson, Ian J

    1997-01-01

    This book describes the propagation of light in biaxial media, the properties of biaxial thin films, and applications such as birefringent filters for tuning the wavelength of dye lasers.A novel feature of the first part is the parallel treatment of Stokes, Jones, and Berreman matrix formalisms in a chapter-by-chapter development of wave equations, basis vectors, transfer matrices, reflection and transmission equations, and guided waves. Computational tools for MATLAB are included.The second part focuses on an emerging planar technology in which anisotropic microstructures are formed by obliqu

  12. Experiment to measure vacuum birefringence: Conceptual design

    Science.gov (United States)

    Mueller, Guido; Tanner, David; Doebrich, Babette; Poeld, Jan; Lindner, Axel; Willke, Benno

    2016-03-01

    Vacuum birefringence is another lingering challenge which will soon become accessible to experimental verification. The effect was first calculated by Euler and Heisenberg in 1936 and is these days described as a one-loop correction to the differential index of refraction between light which is polarized parallel and perpendicular to an external magnetic field. Our plan is to realize (and slightly modify) an idea which was originally published by Hall, Ye, and Ma using advanced LIGO and LISA technology and the infrastructure of the ALPS light-shining-through-walls experiment following the ALPS IIc science run. This work is supported by the Deutsche Forschungsgemeinschaft and the Heising-Simons Foundation.

  13. Direct measurement of birefringence in ion-exchanged planar waveguides

    Science.gov (United States)

    Fazio, E.; Ramadan, W. A.; Bertolotti, M.; Righini, G. C.

    1996-08-01

    A direct measurement of the birefringence of a planar waveguide obtained by Na+ - K + ion exchange was performed with a double Lloyd interferometer. The results are compared with those obtained by a round-robin test involving the same sample. Birefringence of as much as Delta n=(2.0+/-0.2) \\times 10-3 was measured.

  14. Sensing characteristics of birefringent microstructured polymer optical fiber

    DEFF Research Database (Denmark)

    Szczurowski, Marcin K.; Frazao, Orlando; Baptista, J. M.;

    2011-01-01

    We experimentally studied several sensing characteristics of a birefringent microstructured polymer optical fiber. The fiber exhibits a birefringence of the order 2×10-5 at 1.3 μm because of two small holes adjacent to the core. In this fiber, we measured spectral dependence of phase and group mo...

  15. Study of stress birefringence for 193-nm immersion photomasks

    Science.gov (United States)

    Cotte, Eric; Selle, Michael; Bubke, Karsten; Teuber, Silvio

    2005-06-01

    The goal of the present study was to investigate and quantify reticle stress birefringence in exposure conditions. Birefringence can arise in fused silica photomask substrates due to their state of stress, and cause optical effects such as phase front distortion, ray bifurcation, and polarization changes. These effects potentially produce image blurring and illumination non-uniformity, leading to lower resolution and CD variations, respectively. The main sources of substrate stress studied were the absorber stack, the mounting of a pellicle, and the impact of initial reticle bow when chucking in an exposure tool. Jones calculus was used to relate birefringence at discrete locations in the reticle, derived from the state of stress, to the net birefringence experienced by light passing through the mask. Experimentally-obtained birefringence data as well as analytical calculations of stress birefringence caused by known states of stress were used to validate the models. These results can then be compared to photomask birefringence specifications or employed in optical simulations to determine the precise impact of this substrate stress birefringence.

  16. Birefringence of silica hydrogels prepared under high magnetic fields reinvestigated

    International Nuclear Information System (INIS)

    Birefringence is an indicator of structural anisotropy of materials. We measured the birefringence of Pb(II)-doped silica hydrogels prepared under a high magnetic field of various strengths. Because the silica is diamagnetic, one does not expect the structural anisotropy induced by a magnetic field. In previous work (Mori, Kaito and Furukawa 2008 Mater. Lett. 62 3459–61), we prepared samples in cylindrical cells made of borosilicate glass and obtained a preliminary result indicating a negative birefringence for samples prepared at 5 T with the direction of the magnetic field being the optic axis. We have measured the birefringence of Pb(II)-doped silica hydrogels prepared in square cross-sectional cells made of quartz and overturned the previous conclusion. Interestingly, the magnetic-influenced silica hydrogels measured have been classified into four classes: two positive birefringent ones, a no birefringent one, and a negative birefringent one. Proportionality between birefringence and the strength of magnetic field is seen for the former two. (paper)

  17. Modelling birefringence in isolated elliptical core photonic crystal fibers

    DEFF Research Database (Denmark)

    Nielsen, Martin Dybendal; Vienne, Guillaume; Jensen, Jacob Riis;

    2001-01-01

    A simple model for calculation of the birefringence in asymmetric isolated core PCFs employing approximation with an ellipsoid suspended in air is presented. Birefringence values in the order of 10-2 are obtained and comparison with both calculations based on a SEM picture of a real fiber and...

  18. Carrier and chain formation dependence of birefringence in magnetic fluids

    Science.gov (United States)

    Abu-Safia, H.; Abu-Aljarayesh, I.; El-Ghanem, H. M.; Yusuf, N. A.

    1992-01-01

    Measurements of the birefringence in Fe 3O 4 magnetic fluids were undertaken in the temperature range 190-313 K in magnetic fields up to 0.7 kOe. Our results show that the birefringence increases with temperature exhibiting a maximum near the melting point, Tm, of the liquid carrier (kerosene, decalin and Isopar M). For T > Tm the birefringence follows a generalized Curie-Weiss law yielding positive ordering temperatures for the three samples. Moreover, our results show that the birefringence behaves irreversibly with temperature, in the decalin based sample. The results also show that the magnitude of the birefringence and the shape of the maximum change with the applied magnetic fields.

  19. Note: Ultra-low birefringence dodecagonal vacuum glass cell

    Science.gov (United States)

    Brakhane, Stefan; Alt, Wolfgang; Meschede, Dieter; Robens, Carsten; Moon, Geol; Alberti, Andrea

    2015-12-01

    We report on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence Δn of each window with the cell under vacuum conditions, obtaining values around 10-8. After baking the cell at 150 °C, we reach a pressure below 10-10 mbar. In addition, each window is antireflection coated on both sides, which is highly desirable for quantum optics experiments and precision measurements.

  20. Note: Ultra-low birefringence dodecagonal vacuum glass cell

    Energy Technology Data Exchange (ETDEWEB)

    Brakhane, Stefan, E-mail: brakhane@iap.uni-bonn.de; Alt, Wolfgang; Meschede, Dieter; Robens, Carsten; Moon, Geol; Alberti, Andrea [Institut für Angewandte Physik, Universität Bonn, Wegelerstr. 8, D-53115 Bonn (Germany)

    2015-12-15

    We report on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence Δn of each window with the cell under vacuum conditions, obtaining values around 10{sup −8}. After baking the cell at 150 °C, we reach a pressure below 10{sup −10} mbar. In addition, each window is antireflection coated on both sides, which is highly desirable for quantum optics experiments and precision measurements.

  1. High Frequency Modulation Method for Measuring of Birefringence

    Directory of Open Access Journals (Sweden)

    Šulc M.

    2013-05-01

    Full Text Available A method of optical birefringence measurement is presented. It uses an el ectro-optic modulator for the high frequency modulation of polarization of the laser beam. The developed optical apparatus exhibits high sensitivity. It is able to measure very small birefringence of samples down to 10-3 rad. The accuracy and sensitivity of the method was checked by measurement of calibrated Sol eil – Babi net compensator. Method can be also used for online and accurate measurement of an optical components birefringence. This application was developed with the aim to measure Cotton-Mouton effect in air and nitrogen.

  2. Photonic quasi-crystal fiber with high birefringence

    Science.gov (United States)

    Liu, Hongfei; Xiao, Wei; Cai, Weicheng; Liu, Exian; Feng, Bo; Wang, Ziming; Liang, Taiyuan; Wang, Shuo; Liu, Jianjun

    2016-03-01

    A high-birefringence photonic quasi-crystal fiber (HB-PQF) based on SiO2 is proposed. The relationships between birefringence and structure parameters and between beat length and structure parameters are researched by finite difference beam propagation method. With the optimization of fiber structure parameters, the birefringence is 1.4207×10-2, which is two orders of magnitude higher than the normally used fiber when the wavelength is 1.55 μm. The radius of the fiber is 6.5 μm. The HB-PQF in a communication sensor will have important application prospects.

  3. The Curie-Weiss behavior of birefringence in ferrofluids

    Science.gov (United States)

    Yusuf, N. A.; Abu-Safia, H.; Abu-Aljarayesh, I.

    1993-05-01

    Measurements of birefringence in an Fe3O4 magnetic fluid with isopar-M as a liquid carrier were undertaken as a function of temperature for 100birefringence increases with temperature exhibiting a maximum at a certain temperature Tm. The position of Tm decreases with increasing field intensity. For T≳Tm the birefringence follows a Curie-Weiss-type behavior. The ordering temperature changes not only in magnitude but also in sign with increasing field intensity, being negative for H≳500 Oe.

  4. Birefringent Microlens Array for Ultra High Resolution HMDs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will be used to analyze, design, model, and test a birefringent microlens array for use in a new type of...

  5. Angular tuning of the magnetic birefringence in rippled cobalt films

    Energy Technology Data Exchange (ETDEWEB)

    Arranz, Miguel A., E-mail: MiguelAngel.Arranz@uclm.es [Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla-La Mancha, Avda. Camilo J. Cela 10, 13071 Ciudad Real (Spain); Colino, José M. [Instituto de Nanociencia, Nanotecnología y Materiales Moleculares, Universidad de Castilla-La Mancha, Campus de la Fábrica de Armas, 45071 Toledo (Spain)

    2015-06-22

    We report the measurement of magnetically induced birefringence in rippled Co films. For this purpose, the magneto-optical properties of ion beam eroded ferromagnetic films were studied using Kerr magnetometry and magnetic birefringence in the transmitted light intensity. Upon sufficient ion sculpting, these ripple surface nanostructures developed a defined uniaxial anisotropy in the in-plane magnetization, finely tuning the magnetic birefringence effect. We have studied its dependence on the relative orientation between the ripple direction and the magnetic field, and found this effect to be dramatically correlated with the capability to neatly distinguish the mechanisms for the in-plane magnetization reversal, i.e., rotation and nucleation. This double refraction corresponds univocally to the two magnetization axes, parallel and perpendicular to the ripples direction. We have also observed that tuned birefringence in stack assemblies of rippled Co films, which enables us to technically manipulate the number and direction of refraction axes.

  6. Birefringence Determination of Magnetic Moments of Magnetotactic Bacteria

    OpenAIRE

    Rosenblatt, Charles; de Araujo, F. Flavio Torres; Frankel, Richard B.

    1982-01-01

    A birefringence technique is used to determine the average magnetic moments of magnetotactic bacteria in culture. Differences in are noted between live and dead bacteria, as well as between normal density and high density samples of live bacteria.

  7. Form Birefringence in Thin Films with Oblique Columnar Structures

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-Guo; SHAO Jian-Da; WANG Su-Mei; HE Hong-Bo; FAN Zheng-Xiu

    2005-01-01

    @@ Effective medium theory is useful for designing optical elements with form birefringent subwavelength structures. Thinfilms fabricated by oblique deposition are similar to the two-dimensional surface relief subwavelength gratings. We use the effective medium theory to calculate the anisotropic optical properties of the thin films with oblique columnar structures. The effective refractive indices and the directions are calculated from effective medium theory. It is shown that optical thin films with predetermined refractive indices and birefringence may be engineered.

  8. A method to measure vacuum birefringence at FCC-ee

    OpenAIRE

    Uggerhøj, Ulrik I.; Wistisen, Tobias N.

    2016-01-01

    It is well-known that the Heisenberg-Euler-Schwinger effective Lagrangian predicts that a vacuum with a strong static electromagnetic field turns birefringent. We propose a scheme that can be implemented at the planned FCC-ee, to measure the nonlinear effect of vacuum birefringence in electrodynamics arising from QED corrections. Our scheme employs a pulsed laser to create Compton backscattered photons off a high energy electron beam, with the FCC-ee as a particularly interesting example. The...

  9. Mechanical phase matching of birefringent non-linear crystals

    OpenAIRE

    Deyra, Loïc; Balembois, François; Guilbaud, André; Villeval, Philippe; Georges, Patrick

    2014-01-01

    International audience Second-order nonlinear processes such as second harmonic generation or parametric amplification have found numerous applications in the scientific and industrial world, from micromachining to petawatt laser facilities. These nonlinear interactions are mostly carried out in birefringent crystals because of their low cost and the possibility to operate at high powers Phase-matching configurations in birefringent crystals are determined by their refractive indexes. Here...

  10. Modulation instabilities in birefringent two-core optical fibres

    International Nuclear Information System (INIS)

    Previous studies of the modulation instability (MI) of continuous waves (CWs) in a two-core fibre (TCF) did not consider effects caused by co-propagation of the two polarized modes in a TCF that possesses birefringence, such as cross-phase modulation (XPM), polarization-mode dispersion (PMD) and polarization-dependent coupling (PDC) between the cores. This paper reports an analysis of these effects on the MI by considering a linear-birefringence TCF and a circular-birefringence TCF, which feature different XPM coefficients. The analysis focuses on the MI of the asymmetric CW states in the TCFs, which have no counterparts in single-core fibres. We find that the asymmetric CW state exists when its total power exceeds a threshold (minimum) value, which is sensitive to the value of the XPM coefficient. We consider, in particular, a class of asymmetric CW states that admit analytical solutions. In the anomalous dispersion regime, without taking the PMD and PDC into account, the MI gain spectra of the birefringent TCF, if scaled by the threshold power, are almost identical to those of the zero-birefringence TCF. However, in the normal dispersion regime, the power-scaled MI gain spectra of the birefringent TCFs are distinctly different from their zero-birefringence counterparts, and the difference is particularly significant for the circular-birefringence TCF, which takes a larger XPM coefficient. On the other hand, the PMD and PDC only exert weak effects on the MI gain spectra. We also simulate the nonlinear evolution of the MI of the CW inputs in the TCFs and obtain good agreement with the analytical solutions. (paper)

  11. Patterned birefringent polarization converters fabricated by femtosecond laser direct writing

    OpenAIRE

    Gertus, T.; Kazansky, P. G.

    2014-01-01

    Under certain exposure conditions, focused femtosecond light pulses can induce self-assembled nanogratings inside bulk of fused silica glass. Orientation of nanogratings is always perpendicular to incident light polarization. Induced nanograting period varies from 140 nm to 320 nm. By changing incident light power and polarization orientation we can control induced retardance and slow axis of fabricated birefringent patterns. Induced nanogratings exhibit birefringence that provide retardance ...

  12. Vacuum birefringence in high-energy laser-electron collisions

    CERN Document Server

    King, B

    2016-01-01

    Real photon-photon scattering is a long-predicted phenomenon that is being searched for in experiment in the form of a birefringent vacuum at optical and X-ray frequencies. We present results of calculations and numerical simulations for a scenario to measure this effect using multi-MeV photons generated in the collision of electrons with a laser pulse. We find that the birefringence of the vacuum should be measurable using experimental parameters attainable in the near future.

  13. Current sensors using highly-birefringent bow-tie fibres

    OpenAIRE

    Qian, J.R.; Li, L.

    1986-01-01

    Faraday-effect optical-fibre current sensors have a number of well-known advantages for use in high-voltage transmission systems and other hostile environments. However, these applications have been restricted by the presence of linear birefringence in the fibre which adversely interacts with the Faraday polarisation rotation produced by magnetic fields. Linear birefringence results from (a) intrinsic effects within the fibre (ellipticity, inbuilt thermal-stress) and (b) packaging and co...

  14. Laser Induced Birefringence in Pure Liquids

    Science.gov (United States)

    Harrison, Neil J.

    1991-01-01

    Available from UMI in association with The British Library. Laser induced birefringence or the Optical Kerr effect is a subject that has undergone much research over previous years and is an established technique for the study of many classes of materials. To date the measurements on various media have been characterized by the substantial time required to obtain results and the generally poor sensitivity of the apparatus used. This work describes the development of a new apparatus which is the first in the field to automate the signal capture and analysis utilizing a 1 Gigasample/second digitizing oscilloscope connected to a microcomputer to provide fast, accurate transient analysis. Careful design of the apparatus enabled operation at two inducing wavelengths of 532nm and 1064nm. The sensitivity and accuracy of the apparatus coupled with the rapid transient evaluation was tested on a number of well characterized samples including benzene, nitrobenzene, toluene and benzoyl chloride and was found to give excellent agreement with other workers. The apparatus was used to investigate the properties of the organic pure liquid series the n-alkanes before making the first measurements on the 1-alkenes, 1-alkynes, alcohols, carboxylic acids and three alkdienes. Results from these experiments were used to evaluate the contributions of sigma and pi bonds to the Optical Kerr effect in simple organic molecules. A review of all previously published Optical Kerr effect results for pure liquids was also carried out and the first comprehensive table of results complied.

  15. Optical rheology of porcine sclera by birefringence imaging.

    Directory of Open Access Journals (Sweden)

    Masahiro Yamanari

    Full Text Available PURPOSE: To investigate a relationship between birefringence and elasticity of porcine sclera ex vivo using polarization-sensitive optical coherence tomography (PS-OCT. METHODS: Elastic parameters and birefringence of 19 porcine eyes were measured. Four pieces of scleral strips which were parallel to the limbus, with a width of 4 mm, were dissected from the optic nerve head to the temporal side of each porcine eye. Birefringence of the sclera was measured with a prototype PS-OCT. The strain and force were measured with a uniaxial material tester as the sample was stretched with a speed of 1.8 mm/min after preconditioning. A derivative of the exponentially-fitted stress-strain curve at 0% strain was extracted as the tangent modulus. Power of exponential stress-strain function was also extracted from the fitting. To consider a net stiffness of sclera, structural stiffness was calculated as a product of tangent modulus and thickness. Correlations between birefringence and these elastic parameters were examined. RESULTS: Statistically significant correlations between birefringence and all of the elastic parameters were found at 2 central positions. Structural stiffness and power of exponential stress-strain function were correlated with birefringence at the position near the optic nerve head. No correlation was found at the position near the equator. CONCLUSIONS: The evidence of correlations between birefringence and elasticity of sclera tested uniaxially was shown for the first time. This work may become a basis for in vivo measurement of scleral biomechanics using PS-OCT.

  16. Measurements of flow-induced birefringence in microfluidics.

    Science.gov (United States)

    Sun, Chen-Li; Huang, Hung-Yen

    2016-01-01

    In this study, we demonstrate the use of a microscopic circular polariscope to measure the flow-induced birefringence in a microfluidic device that represents the kinematics of fluid motion optically. Unlike the commercial birefringence microscope employed in the previous studies, our approach is able to provide direct measurement of retardance, which quantifies the difference in refractive index of the fluid experienced by the ordinary and extraordinary rays, from one single image frame. This capability facilitates unsteady full-field quantitation of flow-induced birefringence in microfluidics that has never been achieved before. At low flow rates, we find that the value of the retardance is independent of the microfluidic design and proportional to the nominal strain rates. This linearity bridges the measurement of birefringence and the deformation rate in the microflow environment, which yields the stress information of the fluid flow. In addition, the μPIV results confirm that both extensional and shear strain rates contribute to the flow-induced birefringence so that the retardance distribution can be used to represent the field of the principal strain rate in a microfluidic device. The outcome of this study proves that our approach provides a non-invasive method that enables an intuitive full-field representation of stress in the instantaneous flow field in a microfluidic device. PMID:26858809

  17. Deposition, Characterization, And Simulation Of Thin Films With Form Birefringence

    Science.gov (United States)

    Jacobson, M. R.; Horowitz, F.; Liao, Bangjun

    1984-12-01

    Birefringence in optical thin films due to structure on a scale large compared to atoms but small compared to optical wavelengths, known as form birefringence (FB), was observed almost a century ago. More recently, studies of obliquely deposited metal films stimulated new interest in birefringent films. The link between structure, which is predominantly columnar in evaporated thin films, and birefringence has been conclusively demonstrated through ellipsometric measurement and modeling. Direct measurements of form birefringence are especially tedious in tilted films, since essentially four quantities must be derived: three indices of refraction and the film thickness. Clearly, four measurements are required; Horowitz' used an ellipsometric method to perform such measurements on a zirconium oxide (Zr02) film. Later, a 4.6-μm-thick film of Zr02 was obliquely deposited; spectrophotometric measurements revealed its utility as a half-wave plate. A parallel effort directed at understanding FB films through computer simulations has been undertaken by Sikkens and Liao. These simulations can be specialized to include defects, epitaxy, and anisotropic surface mobility. Applications of obliquely deposited FB films of familiar thin film materials can be anticipated if their structure and performance can be more thoroughly understood.

  18. Birefringence enhancement in annealed TiO2 thin films

    Science.gov (United States)

    van Popta, Andy C.; Cheng, June; Sit, Jeremy C.; Brett, Michael J.

    2007-07-01

    Postdeposition thermal annealing is used to enhance the form birefringence of nanostructured TiO2 thin films grown by electron-beam evaporation using the serial bideposition technique. Thin films were grown on fused silica substrates using oblique deposition angles between 60° and 75° and repetitive 180° substrate rotations to produce birefringent thin films that are structurally anisotropic. Postdeposition annealing in air, between 200 and 900°C, was used to increase the form birefringence of the films by changing the TiO2 phase from the as-deposited amorphous state to a polycrystalline state that exhibits a greater inherent density and larger bulk refractive index. The optical properties, microstructure, and crystallinity were characterized by Mueller matrix ellipsometry, scanning electron microscopy, atomic force microscopy, and x-ray diffraction. It was found that the in-plane birefringence increased significantly upon thermal annealing, in some cases yielding birefringence values that doubled in magnitude, from 0.11 to 0.22 at a wavelength of 550nm for films annealed at 400°C.

  19. Mechanical phase matching of birefringent non-linear crystals.

    Science.gov (United States)

    Deyra, Loïc; Balembois, François; Guilbaud, André; Villeval, Philippe; Georges, Patrick

    2014-09-22

    Second-order nonlinear processes such as second harmonic generation or parametric amplification have found numerous applications in the scientific and industrial world, from micromachining to petawatt laser facilities. These nonlinear interactions are mostly carried out in birefringent crystals because of their low cost and the possibility to operate at high powers Phase-matching configurations in birefringent crystals are determined by their refractive indexes. Here, we show that an important mechanical stress can be used to significantly change the phase-matching properties of a birefringent crystal. As an example, we demonstrate the shift of second harmonic non-critical phase matching wavelength of LiB3O5 (LBO) crystal at room temperature from 1200 nm to 1120 nm by applying compressive forces up to 100 MPa. We believe that this mechanical phase matching can be used as an additional degree of freedom to optimize nonlinear optical frequency mixing geometries. PMID:25321800

  20. Terahertz generation by optical rectification in uniaxial birefringent crystals

    CERN Document Server

    Rowley, J D; Zawilski, K T; Schunemann, P G; Giles, N C; Bristow, A D

    2012-01-01

    The angular dependence of terahertz (THz) emission from birefringent crystals can differ significantly from that of cubic crystals. Here we consider optical rectification in uniaxial birefringent materials, such as chalcopyrite crystals. The analysis is verified in a (110)-cut ZnGeP2 and compared to (zincblende) GaP. Although the structures share the same nonzero second-order tensor elements, birefringence causes the pump pulse polarization to evolve as it propagates through the crystal, resulting in a drastically different angular dependence in chalcopyrite crystals. The analysis is extended to predict the response from {012}- and (114)-cut chalcopyrite crystals, revealing an increase in the maximum emission in comparison to (110)-cut crystals.

  1. Highly Nonlinear and Birefringent Spiral Photonic Crystal Fiber

    Directory of Open Access Journals (Sweden)

    S. Revathi

    2014-01-01

    Full Text Available We propose and design a spiral photonic crystal fiber with elliptical air holes for achieving high birefringence, large nonlinearity, and negative dispersion. The structure is designed using chalcogenide glass (As2S3 for different ellipticity ratios of air holes in the cladding and the effect on various properties is observed. The proposed structure has birefringence of the order 10−2, nonlinearity of 26739.42 W−1 m−1, and dispersion of −1136.69 at 0.85 μm. An accurate numerical approach based on finite element method is used for the design and simulation of the structure. Due to high birefringence and negative dispersion, the proposed structure can be used for polarization control and dispersion compensation, respectively.

  2. Highly birefringent, low-loss liquid crystals for terahertz applications

    Directory of Open Access Journals (Sweden)

    M. Reuter

    2013-07-01

    Full Text Available With growing interest in switchable devices for the THz frequency range, there is a strong demand for liquid crystals (LC exhibiting both a high birefringence and a low absorption. We present the refractive index and absorption coefficient of the liquid crystal mixtures 1852 and 1825 in the frequency range between 0.2 and 2.5 THz. Both mixtures are designed specifically for high birefringence Δn of 0.32 and 0.38, respectively, in the THz region. In addition, they show low absorption coefficients for both ordinary and extraordinary polarization. This low absorbance in combination with the high birefringence makes these LCs particularly well suited for applications in switchable devices for THz optics.

  3. Birefringent neutron prisms for spin echo scattering angle measurement

    Energy Technology Data Exchange (ETDEWEB)

    Pynn, Roger, E-mail: rpynn@indiana.ed [Indiana University, Bloomington, IN (United States); Oak Ridge National Laboratory, Oak Ridge, TN (United States); Fitzsimmons, M.R. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lee, W.T. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Stonaha, P.; Shah, V.R.; Washington, A.L. [Indiana University, Bloomington, IN (United States); Kirby, B.J.; Majkrzak, C.F.; Maranville, B.B. [National Institute of Standards and Technology (United States)

    2009-09-01

    In the first decade of the 19th century, an English chemist, William Wollaston, invented an arrangement of birefringent prisms that splits a beam of light into two spatially separated beams with orthogonal polarizations. We have constructed similar devices for neutrons using triangular cross-section solenoids and employed them for Spin Echo Scattering Angle Measurement (SESAME). A key difference between birefringent neutron prisms and their optical analogues is that it is hard to embed the former in a medium which has absolutely no birefringence because this implies the removal of all magnetic fields. We have overcome this problem by using the symmetry properties of the Wollaston neutron prisms and of the overall spin echo arrangement. These symmetries cause a cancellation of Larmor phase aberrations and provide robust coding of neutron scattering angles with simple equipment.

  4. Electric birefringence anomaly of solutions of ionically charged anisometric particles.

    Science.gov (United States)

    Hoffmann, H; Gräbner, Dieter

    2015-02-01

    The term "electric birefringence anomaly" is known as the electric birefringence (EB) signal that occurs in solutions of ionically charged anisometric particles in a narrow concentration region. The signal is of opposite sign to the normal birefringence that occurs below and above this narrow concentration region. The normal electric birefringence signals in the dilute and more concentrated regions are due to the orientation of the particles in the direction of the applied electric field. The origin for the anomalous signal was not completely understood until now. The article summarises previous results in which the anomalous results had been observed but not well understood. It shows that the birefringence anomaly occurs in systems as diverse as micellar solutions, polyelectrolytes, solutions of clays, viruses and fibres. In all these systems the anomaly signals are present at the concentration when the length of the colloidal particles including the thickness of the electric double layer are about the same as the mean distance between the colloidal particles. Under these conditions the electric double layers of the particles overlap along the main axis of the particles but not in the direction across the particles. As a consequence of this situation a dipole is built up across the particles by the migration of the counter-ions of the particles in the electric field and this dipole leads to an orientation of the particles perpendicular to the electric field. The anomalous signal can usually be observed simultaneously with the normal signal. The amplitude of the anomalous signal can be larger than the amplitude of the normal signal. As a consequence the total birefringence changes its sign in the anomalous concentration region. The anomaly signal of the clays can also be explained by a fluctuating dipole around the particles, which is due to the fact that the centre of the ionic charges of the particles does not fall on the centre of the ionic charge of the counter

  5. A birefringent cavity He-Ne laser and optical feedback

    Institute of Scientific and Technical Information of China (English)

    Liu Gang; Zhang Shu-Lian; Li Yan; Zhu Jun

    2004-01-01

    Strong modes competition makes only one of o-light and e-light oscillate in a birefringent dual-frequency laser when the angle between the crystalline axis and the laser beam is nearly zero. When the oscillated mode is in a different part of the gain curve, the detected intensity curves of o-light and e-light are quite different in the existence of optical feedback. The curves are divided into five cases. Three cases of the experimental results can be used for direction discrimination. The polarization characteristics of the birefringent cavity He-Ne laser are also discussed without optical feedback.

  6. Ultraviolet-induced birefringence in hydrogen-loaded optical fiber

    DEFF Research Database (Denmark)

    Canning, John; Deyerl, Hans-Jürgen; Sørensen, Henrik Rokkjær; Kristensen, Martin

    2005-01-01

    role of hydrogen and deuterium in the UV-induced process. Previous arguments for the origins are systematically ruled out by reviewing existing literature. We note that the birefringence is made up of at least two components with different thermal stabilities, one consistent simply with molecular...... hydrogen being present in the system. Overall the birefringence, by deduction, is associated with anisotropy in hydrogen reactions within the fiber. As a result they lead, through known mechanisms of dilation in glass, to anisotropic stress relaxation that can be annealed out, with or without hydrogen...

  7. Utilization of Birefringent Fiber as Sensor of Temperature Field Disturbance

    Directory of Open Access Journals (Sweden)

    F. Dvorak

    2009-12-01

    Full Text Available The paper deals with utilization of induced birefringence sensitivity to temperature field in birefringent optical fibers. The propagating optical wave and optical fibers are described by means of coherency and Jones matrices, which are decomposed into unitary matrix and spin matrices. The development of polarization caused by temperature field is interpreted on the Poincare sphere by means of MATLAB® environment. The temperature sensitivity of Panda and bow-tie fiber has been measured for circular polarization excitation. Curves of intensity fluctuation caused by the temperature dependence are presented.

  8. Flow birefringence in lyotropic mixtures in the isotropic phase

    International Nuclear Information System (INIS)

    The flow-induced birefringence (δn) in lyotropic mixtures in the isotropic phase (ISO) was measured by means of optical techniques. As a function of temperature, the ISO is surrounded by two lamellar (LAM) phases. The shear flow produced by a perturbation in ISO induces a birefringent phase, which relaxes back to ISO with a typical relaxation time τ. τ increases near the transition to the more ordered LAM phases, and the behavior of τ versus temperature indicates the existence of a virtual nematic phase in the isotropic domain

  9. Zero-field birefringence of biocompatible magnetic fluids: A concentration dependence investigation

    International Nuclear Information System (INIS)

    Zero-field birefringence was used to investigate maghemite-based biocompatible magnetic fluids surface-coated with citrate. The model used to analyze the birefringence signal considers the dipolar magnetic interaction among dimers and the onset of a nematic phase near the sample holder surface. The data show that zero-field birefringence grows with sample dilution

  10. Riemannian light cone from vanishing birefringence in premetric vacuum electrodynamics

    CERN Document Server

    Lämmerzahl, C; L{\\"a}mmerzahl, Claus; Hehl, Friedrich W.

    2004-01-01

    We consider premetric electrodynamics with a local and linear constitutive law for the vacuum. Within this framework, we find quartic Fresnel wave surfaces for the propagation of light. If we require vanishing birefringence in vacuum, then a Riemannian light cone is implied. No proper Finslerian structure can occur. This is generalized to dynamical equations of any order.

  11. Chirped optical solitons in single-mode birefringent fibers

    Science.gov (United States)

    Mahmood, M. F.

    1996-12-01

    The trapping behavior of two chirped solitons forming a bound state in a single-mode birefringent fiber is investigated on the basis of a model of coupled nonlinear Schroedinger equations. The positive initial chirp plays an important role in controlling the threshold amplitude for soliton trapping without causing excessive pulse broadening.

  12. Water in oil microemulsions : transient electric birefringence response

    OpenAIRE

    Guering, P.; Cazabat, A.M.

    1983-01-01

    The structure of water in oil microemulsions has been investigated using transient electric birefringence. At low water concentrations, transient coalescence of droplets is observed. At higher water concentrations, the Kerr signal probes density fluctuations. A fast negative response is attributed to the relaxation of interfacial layers. Further work is under way to make these preliminary results more quantitative.

  13. Sprayable birefringent coating enables strain measurements on large surfaces

    Science.gov (United States)

    Humphrey, F. T.; Mcgee, W. M.

    1966-01-01

    Birefringent coating for strain measurements on large surfaces contains constituents that can be premixed and sprayed as a single component with conventional paint spray equipment. Elevated temperatures are not required for spraying or curing of the coating material which has long pot life.

  14. Numerical simulation of laser focusing properties inside birefringent crystal.

    Science.gov (United States)

    Deng, Leimin; Liu, Peng; Duan, Jun; Zeng, Xiaoyan; Wu, Baoye; Wang, Xizhao

    2016-02-01

    The transmission properties of a focused laser inside anisotropic material are complex due to the birefringent effect, which has remarkable influence on the light distribution and frequency multiplication efficiency of crystals. Meanwhile, it will also affect the laser micromachining precision of birefringent materials with random polarization. In this study, ray tracing and diffraction integral methods were proposed to develop the mathematical model of a laser focused through an isotropic medium into a KDP crystal. Using these models, the focusing properties and 3D light intensity distribution of a focused laser inside a KDP crystal at different orientations were investigated. The research shows that the size and shape of the E-ray focus will distort, and its peak power density decreases rapidly with the decrease of the angle between the optical axis and the crystal surface. Meanwhile, the focal position of the E-ray will also move with the change of optical axis orientation. Based on the simulated results, an approximate 3D light intensity equation of a laser focused into birefringent material was also proposed, which is in good agreement with the theoretical analysis. The related simulated results have an important engineering value for nonlinear optics and laser processing of birefringent materials. PMID:26836091

  15. Influence of birefringence in the instability spectra of oppositely directed coupler with negative index material channel

    Science.gov (United States)

    Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.; Maimistov, Andrei I.

    2016-02-01

    A theoretical investigation on the influence of birefringence in the modulational instability (MI) spectra of an oppositely directed coupler (ODC) with a negative index material (NIM) channel is presented. We study the effect of birefringence on MI in linear and circular birefringent ODCs for both normal and anomalous dispersion regimes. It is found that besides the instability band due to nonlinear positive index material (PIM) and negative index material (NIM) channels, new symmetric instability regions are observed as a result of birefringent effects. Also defocusing nonlinearity suppresses the NIM band in the normal dispersion regime, but in the anomalous dispersion regime the defocusing nonlinearity enhances the gain of the NIM band. In contrast to the case of linear birefringence, in terms of MI gain from circular birefringence, only two birefringent bands dominate: the inherently PIM and NIM bands. This preponderance is attributed to the fact that the cross-phase modulation effect for the case of circular birefringence is stronger, thus allowing a better coupling between the beams, which results in the enhancement of the gain. Therefore, the manipulation of MI and solitons in an ODC is better performed when the birefringence is circular rather than linear. Here we report how to generate and manipulate MI and solitons in birefringent ODCs with a particular emphasis on a NIM channel.

  16. Hydrostatic Pressure Sensing with High Birefringence Photonic Crystal Fibers

    Science.gov (United States)

    Fávero, Fernando C.; Quintero, Sully M. M.; Martelli, Cicero; Braga, Arthur M.B.; Silva, Vinícius V.; Carvalho, Isabel C. S.; Llerena, Roberth W. A.; Valente, Luiz C. G.

    2010-01-01

    The effect of hydrostatic pressure on the waveguiding properties of high birefringence photonic crystal fibers (HiBi PCF) is evaluated both numerically and experimentally. A fiber design presenting form birefringence induced by two enlarged holes in the innermost ring defining the fiber core is investigated. Numerical results show that modal sensitivity to the applied pressure depends on the diameters of the holes, and can be tailored by independently varying the sizes of the large or small holes. Numerical and experimental results are compared showing excellent agreement. A hydrostatic pressure sensor is proposed and demonstrated using an in-fiber modal interferometer where the two orthogonally polarized modes of a HiBi PCF generate fringes over the optical spectrum of a broad band source. From the analysis of experimental results, it is concluded that, in principle, an operating limit of 92 MPa in pressure could be achieved with 0.0003% of full scale resolution. PMID:22163435

  17. CMB Polarization Systematics, Cosmological Birefringence and the Gravitational Waves Background

    CERN Document Server

    Pagano, Luca; De Troia, Grazia; Gubitosi, Giulia; Masi, Silvia; Melchiorri, Alessandro; Natoli, Paolo; Piacentini, Francesco; Polenta, Gianluca

    2009-01-01

    Cosmic Microwave Background experiments must achieve very accurate calibration of their polarization reference frame to avoid biasing the cosmological parameters. In particular, a wrong or inaccurate calibration might mimic the presence of a gravitational wave background, or a signal from cosmological birefringence, a phenomenon characteristic of several non-standard, symmetry breaking theories of electrodynamics that allow for \\textit{in vacuo} rotation if the polarization direction of the photon. Noteworthly, several authors have claimed that the BOOMERanG 2003 (B2K) published polarized power spectra of the CMB may hint at cosmological birefringence. Such analyses, however, do not take into account the reported calibration uncertainties of the BOOMERanG focal plane. We develop a formalism to include this effect and apply it to the BOOMERanG dataset, finding a cosmological rotation angle $\\alpha=-4.3^\\circ\\pm4.1^\\circ$. We also investigate the expected performances of future space borne experiment, finding t...

  18. Lorentz violation induced vacuum birefringence and its astrophysical consequences

    CERN Document Server

    Shao, Lijing

    2011-01-01

    A linearly polarized light composes of two circularly polarized modes, which, in the electromagnetism of loop quantum gravity and Lorentz-violating effective field theories, can have different phase velocity and group velocity. This phenomenon is termed as "vacuum birefringence", in analogy of lights within anisotropic medium. We study vacuum birefringence by incorporating differences in both phase velocity and group velocity in our Ansatz, and obtain analytical expressions of propagation behaviors and time evolutions of Stocks parameters of an originally linearly polarized light from astrophysical origin. Two novel phenomenons, namely, "peak doubling" and "de-polarization", are expected to emerge after the light traveling through a cosmological distance, from $\\gamma$-ray bursts (GRBs), galaxies, and other astrophysical sources to the earth. We present a detailed derivation to obtain criteria to observe "peak doubling" and "de-polarization", and our results show that these two criteria turn out to be the sam...

  19. POLARBEAR constraints on cosmic birefringence and primordial magnetic fields

    Science.gov (United States)

    Ade, Peter A. R.; Arnold, Kam; Atlas, Matt; Baccigalupi, Carlo; Barron, Darcy; Boettger, David; Borrill, Julian; Chapman, Scott; Chinone, Yuji; Cukierman, Ari; Dobbs, Matt; Ducout, Anne; Dunner, Rolando; Elleflot, Tucker; Errard, Josquin; Fabbian, Giulio; Feeney, Stephen; Feng, Chang; Gilbert, Adam; Goeckner-Wald, Neil; Groh, John; Hall, Grantland; Halverson, Nils W.; Hasegawa, Masaya; Hattori, Kaori; Hazumi, Masashi; Hill, Charles; Holzapfel, William L.; Hori, Yasuto; Howe, Logan; Inoue, Yuki; Jaehnig, Gregory C.; Jaffe, Andrew H.; Jeong, Oliver; Katayama, Nobuhiko; Kaufman, Jonathan P.; Keating, Brian; Kermish, Zigmund; Keskitalo, Reijo; Kisner, Theodore; Kusaka, Akito; Le Jeune, Maude; Lee, Adrian T.; Leitch, Erik M.; Leon, David; Li, Yun; Linder, Eric; Lowry, Lindsay; Matsuda, Frederick; Matsumura, Tomotake; Miller, Nathan; Montgomery, Josh; Myers, Michael J.; Navaroli, Martin; Nishino, Haruki; Okamura, Takahiro; Paar, Hans; Peloton, Julien; Pogosian, Levon; Poletti, Davide; Puglisi, Giuseppe; Raum, Christopher; Rebeiz, Gabriel; Reichardt, Christian L.; Richards, Paul L.; Ross, Colin; Rotermund, Kaja M.; Schenck, David E.; Sherwin, Blake D.; Shimon, Meir; Shirley, Ian; Siritanasak, Praween; Smecher, Graeme; Stebor, Nathan; Steinbach, Bryan; Suzuki, Aritoki; Suzuki, Jun-ichi; Tajima, Osamu; Takakura, Satoru; Tikhomirov, Alexei; Tomaru, Takayuki; Whitehorn, Nathan; Wilson, Brandon; Yadav, Amit; Zahn, Alex; Zahn, Oliver; Polarbear Collaboration

    2015-12-01

    We constrain anisotropic cosmic birefringence using four-point correlations of even-parity E -mode and odd-parity B -mode polarization in the cosmic microwave background measurements made by the POLARization of the Background Radiation (POLARBEAR) experiment in its first season of observations. We find that the anisotropic cosmic birefringence signal from any parity-violating processes is consistent with zero. The Faraday rotation from anisotropic cosmic birefringence can be compared with the equivalent quantity generated by primordial magnetic fields if they existed. The POLARBEAR nondetection translates into a 95% confidence level (C.L.) upper limit of 93 nanogauss (nG) on the amplitude of an equivalent primordial magnetic field inclusive of systematic uncertainties. This four-point correlation constraint on Faraday rotation is about 15 times tighter than the upper limit of 1380 nG inferred from constraining the contribution of Faraday rotation to two-point correlations of B -modes measured by Planck in 2015. Metric perturbations sourced by primordial magnetic fields would also contribute to the B -mode power spectrum. Using the POLARBEAR measurements of the B -mode power spectrum (two-point correlation), we set a 95% C.L. upper limit of 3.9 nG on primordial magnetic fields assuming a flat prior on the field amplitude. This limit is comparable to what was found in the Planck 2015 two-point correlation analysis with both temperature and polarization. We perform a set of systematic error tests and find no evidence for contamination. This work marks the first time that anisotropic cosmic birefringence or primordial magnetic fields have been constrained from the ground at subdegree scales.

  20. Modulation Instabilities in Birefringent Two-Core Optical Fibers

    CERN Document Server

    Li, J H; Malomed, B A; Chow, K W

    2012-01-01

    Previous studies of the modulation instability (MI) of continuous waves (CWs) in a two-core fiber (TCF) did not consider effects caused by co-propagation of the two polarized modes in a TCF that possesses birefringence, such as cross-phase modulation (XPM), polarization-mode dispersion (PMD), and polarization-dependent coupling (PDC) between the cores. This paper reports an analysis of these effects on the MI by considering a linear-birefringence TCF and a circular-birefringence TCF, which feature different XPM coefficients. The analysis focuses on the MI of the asymmetric CW states in the TCFs, which have no counterparts in single-core fibers. We find that, the asymmetric CW state exists when its total power exceeds a threshold (minimum) value, which is sensitive to the value of the XPM coefficient. We consider, in particular, a class of asymmetric CW states that admit analytical solutions. In the anomalous dispersion regime, without taking the PMD and PDC into account, the MI gain spectra of the birefringen...

  1. POLARBEAR Constraints on Cosmic Birefringence and Primordial Magnetic Fields

    CERN Document Server

    Ade, Peter A R; Atlas, Matt; Baccigalupi, Carlo; Barron, Darcy; Boettger, David; Borrill, Julian; Chapman, Scott; Chinone, Yuji; Cukierman, Ari; Dobbs, Matt; Ducout, Anne; Dunner, Rolando; Elleflot, Tucker; Errard, Josquin; Fabbian, Giulio; Feeney, Stephen; Feng, Chang; Gilbert, Adam; Goeckner-Wald, Neil; Groh, John; Hall, Grantland; Halverson, Nils W; Hasegawa, Masaya; Hattori, Kaori; Hazumi, Masashi; Hill, Charles; Holzapfel, William L; Hori, Yasuto; Howe, Logan; Inoue, Yuki; Jaehnig, Gregory C; Jaffe, Andrew H; Jeong, Oliver; Katayama, Nobuhiko; Kaufman, Jonathan P; Keating, Brian; Kermish, Zigmund; Keskitalo, Reijo; Kisner, Theodore; Kusaka, Akito; Jeune, Maude Le; Lee, Adrian T; Leitch, Erik M; Leon, David; Li, Yun; Linder, Eric; Lowry, Lindsay; Matsuda, Frederick; Matsumura, Tomotake; Miller, Nathan; Montgomery, Josh; Myers, Michael J; Navaroli, Martin; Nishino, Haruki; Okamura, Takahiro; Paar, Hans; Peloton, Julien; Pogosian, Levon; Poletti, Davide; Puglisi, Giuseppe; Raum, Christopher; Rebeiz, Gabriel; Reichardt, Christian L; Richards, Paul L; Ross, Colin; Rotermund, Kaja M; Schenck, David E; Sherwin, Blake D; Shimon, Meir; Shirley, Ian; Siritanasak, Praween; Smecher, Graeme; Stebor, Nathan; Steinbach, Bryan; Suzuki, Aritoki; Suzuki, Jun-ichi; Tajima, Osamu; Takakura, Satoru; Tikhomirov, Alexei; Tomaru, Takayuki; Whitehorn, Nathan; Wilson, Brandon; Yadav, Amit; Zahn, Alex; Zahn, Oliver

    2015-01-01

    We constrain anisotropic cosmic birefringence using four-point correlations of even-parity $E$-mode and odd-parity $B$-mode polarization in the cosmic microwave background measurements made by the POLARBEAR experiment in its first season of observations. We find that the anisotropic cosmic birefringence signal from any parity violating processes is consistent with zero. The Faraday rotation from anisotropic cosmic birefringence can be compared with the equivalent quantity generated by primordial magnetic fields if they existed. The POLARBEAR non-detection translates into a 95% confidence level (C.L.) upper limit of 93 nano-Gauss (nG) on the amplitude of an equivalent primordial magnetic field inclusive of systematic uncertainties. This four-point correlation constraint on Faraday rotation is about 15 times tighter than the upper limit of 1380 nG inferred from constraining the contribution of Faraday rotation to two-point correlations of $B$-modes measured by Planck in 2015. Metric perturbations sourced by pri...

  2. A method to measure vacuum birefringence at FCC-ee

    CERN Document Server

    Uggerhøj, Ulrik I

    2016-01-01

    It is well-known that the Heisenberg-Euler-Schwinger effective Lagrangian predicts that a vacuum with a strong static electromagnetic field turns birefringent. We propose a scheme that can be implemented at the planned FCC-ee, to measure the nonlinear effect of vacuum birefringence in electrodynamics arising from QED corrections. Our scheme employs a pulsed laser to create Compton backscattered photons off a high energy electron beam, with the FCC-ee as a particularly interesting example. These photons will pass through a strong static magnetic field, which changes the state of polarization of the radiation - an effect proportional to the photon energy. This change will be measured by the use of an aligned single-crystal, where a large difference in the pair production cross-sections can be achieved. In the proposed experimental setup the birefringence effect gives rise to a difference in the number of pairs created in the analyzing crystal, stemming from the fact that the initial laser light has a varying st...

  3. A study of dislocations and inclusions in Yttrium Aluminum Garnet crystals with birefringence topography

    OpenAIRE

    Shiu-Ying, Shu; Zhoun-Zhung, Kuo; Duan, Fong

    1980-01-01

    Birefringence images due to dislocations and inclusions in YAG crystals were studied with polarizing microscopy. Birefringence images of dislocations viewed end-on as well as viewed from the side were interpreted by Tanner and Fathers' theory with due considerations of the effect of long-range strain field. The Burgers vectors of dislocations were found to be of the type of [MATH] , and . The effect of long-range strain field on birefringence images was elucidated.

  4. Influence of filler metal on birefringent optical properties of photonic crystal fiber with integrated electrodes

    Science.gov (United States)

    Reyes-Vera, Erick; Torres, Pedro

    2016-08-01

    We present a comprehensive study of the influence of the filler metal on the birefringent optical properties of a photonic crystal fiber containing two integrated electrodes. Bismuth and indium were used to examine the effects of the electrode composition on the temperature sensitivity of this special microstructured fiber. We found that the fiber microstructure significantly influences the metal-induced sensitivity of the wavelength dependent birefringence, making the behavior of the birefringence change strongly with the electrode material. By modeling the anisotropic changes induced by the metal expansion in the refractive index within the fiber we examine the essential features of the fiber birefringence.

  5. Birefringence properties of a polarization maintaining Panda fibre during Bragg grating regeneration

    Science.gov (United States)

    Polz, Leonhard; Jarsen, Andreas; Bartelt, Hartmut; Roths, Johannes

    2015-09-01

    Regeneration of fibre Bragg gratings under application of a high temperature annealing process in a high birefringent polarisation maintaining fibre of type Panda was investigated. During the annealing process, a distinct nonlinearity and hysteresis of the birefringence with temperature was observed. After the temperature process, the birefringence between slow and fast axis at room temperature was nearly doubled, which is in agreement with observations of other researchers. The hysteresis in birefringence might be explained by the crossing of the transition temperature of the stress applying parts and the relief of in-frozen mechanical and thermal stresses.

  6. Birefringence and transmission electron microscopy of maghemite-based biocompatible magnetic fluids

    International Nuclear Information System (INIS)

    Static magnetic birefringence (SMB) and transmission electron microscopy were used to investigate maghemite-based magnetic fluids surface coated with citrate and dispersed in physiologic solution. The model used to investigate the birefringence signal considers the monomer and dimer contributions and dimer magnetic permeability dependence to the applied field. The particle size distribution obtained from the fit of the SMB data is compared to the data obtained from the microscopy. Zero-field birefringence, present in the birefringence data, was also taken into account, and analyzed by the dimer model

  7. Coupled-mode equation of polarization modes of twisted birefringent fibers in a unified coordinate.

    Science.gov (United States)

    Fang, Zujie; Yang, Fei; Cai, Haiwen; Qu, Ronghui

    2013-01-20

    A coupled-mode equation (CME) of twisted birefringent fiber is presented in this paper, which uses the degenerate polarization modes of single-mode fibers as eigenmodes in a unified coordinate. The inconsistency between the coordinate and the rotating principal axis, existing in the previous CME, is solved by conversion to the lab coordinate. The CME gives self-consistent results for fibers with high birefringence or low birefringence and for single-mode fibers as well. Analyses and simulations show the CME gives characteristics of twisted birefringent fiber coincident with the property of polarization-maintaining fibers. PMID:23338204

  8. Low loss, low dispersion and highly birefringent terahertz porous fibers

    CERN Document Server

    Atakaramians, Shaghik; Fischer, Bernd M; Abbott, Derek; Monro, Tanya M

    2008-01-01

    We demonstrate that porous fibers have low effective material loss over an extended frequency range, 4.5 times larger bandwidth than that can be achieved in sub-wavelength solid core fibers. We also show that these new fibers can be designed to have near zero dispersion for 0.5-1 THz resulting to overall less terahertz signal degradation. In addition, it is demonstrated that the use of asymmetrical sub-wavelength air-holes within the core leads to high birefringence ~0.026. This opens up the potential for realization of novel polarization preserving fibers in the terahertz regime.

  9. Nonlinear Cherenkov difference-frequency generation exploiting birefringence of KTP

    Energy Technology Data Exchange (ETDEWEB)

    Ni, R.; Du, L.; Wu, Y.; Hu, X. P., E-mail: xphu@nju.edu.cn; Zou, J.; Zhang, Y.; Zhu, S. N. [National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093 (China); Sheng, Y. [Laser Physics Center, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Arie, A. [School of Electrical Engineering, Faculty of Engineering, Tel-Aviv University, Tel-Aviv 69978 (Israel)

    2016-01-18

    In this letter, we demonstrate the realization of nonlinear Cherenkov difference-frequency generation (CDFG) exploiting the birefringence property of KTiOPO{sub 4} (KTP) crystal. The pump and signal waves were set to be along different polarizations, thus the phase-matching requirement of CDFG, which is, the refractive index of the pump wave should be smaller than that of the signal wave, was fulfilled. The radiation angles and the intensity dependence of the CDFG on the pump wave were measured, which agreed well with the theoretical ones.

  10. Nonlinear Cherenkov difference-frequency generation exploiting birefringence of KTP

    International Nuclear Information System (INIS)

    In this letter, we demonstrate the realization of nonlinear Cherenkov difference-frequency generation (CDFG) exploiting the birefringence property of KTiOPO4 (KTP) crystal. The pump and signal waves were set to be along different polarizations, thus the phase-matching requirement of CDFG, which is, the refractive index of the pump wave should be smaller than that of the signal wave, was fulfilled. The radiation angles and the intensity dependence of the CDFG on the pump wave were measured, which agreed well with the theoretical ones

  11. Multi-wavelength Šolc birefringent filter

    Czech Academy of Sciences Publication Activity Database

    Melich, Radek; Melich, Zbyněk; Šolc, Ivan

    Vol. 7018. Bellingham, Washington : Society of Photo-Optical Instrumentation Engineers, 2008 - (Atad-Ettedgui, E.; Lemke, D.), s. 1-7 ISBN 9780819472281. - (SPIE. 7018). [The Physics of Chromospheric Plasma. Marseille (FR), 23.06.2008-27.06.2008] R&D Projects: GA AV ČR 1QS100820502 Institutional research plan: CEZ:AV0Z20430508 Keywords : Šolc birefringent filter * multiwavelength Subject RIV: BH - Optics, Masers, Lasers http://dx.doi.org/10.1117/12.788814

  12. Birefringent Fourier transform imaging spectrometer with a rotating retroreflector.

    Science.gov (United States)

    Bai, Caixun; Li, Jianxin; Shen, Yan; Zhou, Jianqiang

    2016-08-01

    A birefringent Fourier transform imaging spectrometer with a new lateral shearing interferometer is presented. The interferometer includes a Wollaston prism and a retroreflector. It splits an incident light beam into two shearing parallel parts to obtain interference fringe patterns of an imaging target, which is well established as an aid in reducing problems associated with optical alignment and manufacturing precision. Continuously rotating the retroreflector enables the spectrometer to acquire two-dimensional spectral images without spatial scanning. This technology, with a high work efficiency and low complexity, is inherently compact and robust. The effectiveness of the proposed method is demonstrated by the experimental results. PMID:27472640

  13. Birefringence compensation in single solid-state rods

    International Nuclear Information System (INIS)

    Various methods for compensating birefringence depolarization in solid-state rods are theoretically and experimentally analyzed and compared. Gaussian and flat top beam profiles are investigated. The efficiency in depolarization loss reduction using different techniques is discussed in terms of beam profile, rod fill factor, and thermal heat load. In Nd:yttrium-aluminum-garnet, the depolarization loss can be efficiently reduced below 5% with a compensating quarter-waveplate, up to 20 W heat load for a flat top beam and up to 70 W for a gaussian beam. (c) 2000 American Institute of Physics

  14. X-ray natural birefringence in reflection from graphene

    Science.gov (United States)

    Jansing, C.; Mertins, H.-Ch.; Gilbert, M.; Wahab, H.; Timmers, H.; Choi, S.-H.; Gaupp, A.; Krivenkov, M.; Varykhalov, A.; Rader, O.; Legut, D.; Oppeneer, P. M.

    2016-07-01

    The existence of natural birefringence in x-ray reflection on graphene is demonstrated at energies spanning the carbon 1 s absorption edge. This new x-ray effect has been discovered with precision measurements of the polarization-plane rotation and the polarization-ellipticity changes that occur upon reflection of linearly polarized synchrotron radiation on monolayer graphene. Extraordinarily large polarization-plane rotations of up to 30∘, accompanied by a change from linearly to circularly polarized radiation have been measured for graphene on copper. Graphene on single crystalline cobalt, grown on tungsten, exhibits rotation values of up to 17∘. Both graphene systems show resonantly enhanced effects at the π* and σ* energies. The results are referenced against those obtained for polycrystalline carbon and highly oriented pyrolytic graphite (HOPG), respectively. As expected, polycrystalline carbon shows negligible rotation, whereas a huge maximum rotation of 140∘ has been observed for HOPG that may be considered a graphene multilayer system. HOPG is found to exhibit such large rotation values over a broad energy range, even well beyond the π* resonance energy due to the contributions of numerous graphene layers. To explain the origin of the observed natural birefringence of graphene, the Stokes parameters as well as the x-ray natural linear dichroism in reflection have been determined. It is shown that the birefringence directly results from the optical anisotropy related to the orthogonal alignment of π* and σ* bonds in the graphene layer. Our polarization analysis reveals a strong bonding of graphene on Co with a reduced σ* excitation energy and a strong tilt of 50 % of the pz orbitals towards diagonal orientation. In contrast, graphene on Cu is weakly bound with an orthogonal orientation of the pz orbitals. Exhibiting such a large natural birefringence that can be controlled through substrate choice, and because of excellent heat conductivity

  15. Sensitive birefringent temperature sensor based on a waveguide ring resonator.

    Science.gov (United States)

    Yu, Xuhui; Ma, Huilian; Jin, Zhonghe; Pan, Ming; Hou, Liwei; Xie, Wei

    2014-04-20

    A sensitive birefringent thermometer based on a SiO2 waveguide ring resonator is demonstrated in this paper. It can be used to fabricate a terahertz thermal detector. The temperature sensitivity is enhanced by the resonances of two polarization modes in the waveguide ring resonator. A high degree of common rejection exists for external influence. A linear temperature range from 6°C to 40°C has been detected with resolution of 0.025°C. PMID:24787604

  16. Annealing of UV-Induced Birefringence in Hydrogen Loaded Germanosilicate Fibres

    DEFF Research Database (Denmark)

    Canning, John; Deyerl, Hans-Jürgen; Sørensen, Henrik Rokkjær;

    2005-01-01

    UV-reduced birefringence in germanosilicate optical fibres loaded with hydrogen is annealed out at low temperatures (125o C). Annealing for induced birefringence in gratings written by either s or p polarised UV light are identical. The results are incosistent with previous models for the origin of...

  17. Extremely High-Birefringent Asymmetric Slotted-Core Photonic Crystal Fiber in THz Regime

    DEFF Research Database (Denmark)

    Islam, Raonaqul; Habib, Selim; Hasanuzzaman, G.K.M.;

    2015-01-01

    We present a thorough numerical analysis of a highly birefringent slotted porous-core circular photonic crystal fiber (PCF) for terahertz (THz) wave guidance. The slot shaped air-holes break the symmetry of the porous-core which offers a very high birefringence whereas the compact geometry of the...

  18. Effects of M Ⅱ stage oocytes zona pellucida birefringence on pregnancy outcome

    Institute of Scientific and Technical Information of China (English)

    Jia Luo; Yan-Wen Xu; Ming-Fang Zhang; Ling Gao; Cong Fang; Can-Quan Zhou

    2013-01-01

    Objective: To explore the effects of different MⅡ stage oocytes zona pellucida birefringence on pregnancy outcome. Methods: A total of 46 couples with infertile which induced by single cause received in-vitro fertilization treatment were analyzed retrospectively, and randomly divided into the high zona birefringence (HZB)/HZB group, HZB/low zona birefringence (LZB) group and LZB/LZB group according to different oocytes zona pellucida birefringence. Intracytoplasmic sperm injection outcome was analyzed and compared. Results: The proportion of HZB oocytes, implantation rate and the pregnancy rate were decreased in three groups (HZB/HZB group>HZB/LZB group>LZB/LZB group) (P0.05). Logistic regression analysis showed that factors affect M Ⅱ stage oocytes zona pellucida birefringence were age, basal FSH level and the LH level on the day of HCG injection. Age and FSH levels were negatively correlated with the single oocyte zona pellucida birefringence; While the LH level on the day of hCG injection was positively correlated with the single oocyte zona pellucida birefringence. Conclusions: The primary influence factors on M Ⅱ stage oocytes zona pellucida are age, basal FSH level and the LH level on the day of hCG injection. The birefringence value of zona pellucida can affect the pregnancy outcome.

  19. Strong modification of the reflection from birefringent layers of semiconductor nanowires by nanoshells

    NARCIS (Netherlands)

    Diedenhofen, S.L.; Algra, R.E.; Bakkers, E.P.A.M.; Gómez Rivas, J.

    2011-01-01

    The propagation of light in layers of vertically aligned nanowires is determined by their unique and extreme optical properties. Depending on the nanowire filling fraction and their diameter, layers of nanowires form strongly birefringent media. This large birefringence gives rise to sharp angle dep

  20. Birefringence and electro-optic effect in epitaxial BST thin films

    International Nuclear Information System (INIS)

    The birefringence and electro-optic (EO) effect of barium strontium titanate ((Ba, Sr)TiO3, BST) epitaxial films formed on strontium titanate single crystal substrates were evaluated using a new system employing transmission geometry. The BST films had a strained lattice with a large lattice parameter along the thickness direction. Small birefringence was induced in the as-deposited film by the alignment of the c-axis in the film plane. The birefringence was enhanced by application of electric field before the measurement of the EO-effect. The electric field dependence of the birefringence was a nearly parabolic without a hysteresis shape, indicating that the EO-effect of BST epitaxial film was dominantly determined by the Kerr effect to reduce the birefringence. The Kerr coefficient of the BST film was determined to be 3.44 x 10-17 m2/V2.

  1. CMB polarization systematics, cosmological birefringence, and the gravitational waves background

    International Nuclear Information System (INIS)

    Cosmic microwave background experiments must achieve very accurate calibration of their polarization reference frame to avoid biasing the cosmological parameters. In particular, a wrong or inaccurate calibration might mimic the presence of a gravitational wave background, or a signal from cosmological birefringence, a phenomenon characteristic of several nonstandard, symmetry breaking theories of electrodynamics that allow for in vacuo rotation of the polarization direction of the photon. Noteworthly, several authors have claimed that the BOOMERanG 2003 (B2K) published polarized power spectra of the cosmic microwave background may hint at cosmological birefringence. Such analyses, however, do not take into account the reported calibration uncertainties of the BOOMERanG focal plane. We develop a formalism to include this effect and apply it to the BOOMERanG dataset, finding a cosmological rotation angle α=-4.3 deg. ±4.1 deg. We also investigate the expected performances of future space borne experiment, finding that an overall miscalibration larger then 1 deg. for Planck and 0.2 deg. for the Experimental Probe of Inflationary Cosmology, if not properly taken into account, will produce a bias on the constraints on the cosmological parameters and could misleadingly suggest the presence of a gravitational waves background.

  2. Magnetic birefringence of iron oxyhydroxide nanoparticles stabilised by sucrose

    International Nuclear Information System (INIS)

    Magnetically induced optical birefringence is used to investigate pharmaceutically important iron-sucrose aqueous suspensions. XRD and TEM measurements of the system of oxyhydroxide particles stabilised by sucrose have shown that this system contains iron oxyhydroxide in the form of 2-5 nm particles. The mineral form of the iron-core is suggested to be akaganeite. Anisotropy of the optical polarizability and magnetic susceptibility of akaganeite nanoparticles are calculated. The permanent dipole moment obtained for the nanoparticles studied was found to be negligible, in agreement with the characteristic superparamagnetic behaviour of the magnetic nanoparticles observed at room temperature. The Neel temperature of these nanoparticles is estimated as below 276 K. The results obtained are discussed against a background of the earlier studies of similar nanoscale systems. - Research highlights: → Polysaccharides iron complex, important in pharmaceutical applications, was studied by magnetic birefringence. → Magnetic and optical properties of the akaganeite core has been obtained. The superparamagnetic behaviour of the core has been confirmed. → The experiment suggests that the Neel temperature of these nanoparticles should be set below 276 K. The results show the importance of the magneto-optical method in recognition of magnetic properties of biologically important substances.

  3. Vacuum birefringence by Compton backscattering through a strong field

    Science.gov (United States)

    Wistisen, Tobias N.; Uggerhøj, Ulrik I.

    2013-09-01

    We propose a novel scheme to measure nonlinear effects in electrodynamics arising from QED corrections. Our theoretical starting point is the Heisenberg-Euler-Schwinger effective Lagrangian which predicts that a vacuum with a strong static electromagnetic field turns birefringent. We propose to employ a pulsed laser to create Compton backscattered photons off a high energy electron beam. These photons will pass through a strong static magnetic field, which according to the QED prediction changes the state of polarization of the radiation—an effect proportional to the photon energy. This change will be measured by using an aligned single crystal, since a large difference in the pair production cross sections at high energies can be achieved with proper orientation of the crystal. As an example we will consider the machine, LHeC, under consideration at CERN as the source of these electrons, and an LHC dipole magnet as the source of the strong static magnetic field. In the proposed experimental setup the birefringence effect will be manifested in a difference in the number of pairs created in the polarizer crystal as the initial laser light has a varying state of polarization, achieved with a rotating quarter wave plate. This will be seen as a clear peak in the Fourier transform spectrum of the pair-production rate signal, which can be obtained with 3 hours of measurement. We also comment on the sensitivity of the experiment, to the existence of an axion, a hypothetical spin-0 particle that couples to two photons.

  4. Group-Velocity-Matched Three Wave Mixing in Birefringent Crystals

    Energy Technology Data Exchange (ETDEWEB)

    SMITH,ARLEE V.

    2000-12-12

    We show that the combination of pulse-front slant, k-vector tilt, and crystal birefringence often permits exact matching of both phase and group velocities in three wave mixing in birefringent crystals. This makes possible more efficient mixing of short light pulses, and it permits efficient mixing of chirped or broad bandwidth light. We analyze this process and present examples. Differences in the group velocities of the three interacting waves in a nonlinear crystal often limits the effective interaction length. For example, in mixing very short pulses, temporal walk off can stretch the pulses in time unless the crystal is very short. Efficient mixing with such short crystals requires high irradiances, but the irradiances are limited by higher order nonlinear effects such as intensity-dependent refractive index and two-photon absorption. Improved matching of the group velocities can alleviate this problem, allowing longer crystal and lower irradiances. Similarly, for high energy pulses, practical limits on crystal apertures mandate temporally stretching the pulses to reduce irradiances. For the resulting chirped pulses, temporal walk off restricts the chirp range unless the group velocities are well matched. In addition to perfectly matching the group velocities of all three waves, it is sometimes useful to match two velocities, such as the signal and idler in parametric amplification, permitting broadband parametric amplification, or to arrange the velocities of two inputs to bracket the generated sum frequency pulse, giving pulse compression under suitable circumstances.

  5. Zeeman-Birefringence He-Ne Dual Frequency Lasers

    Institute of Scientific and Technical Information of China (English)

    JIN Yu-Ye; ZHANG Shu-Lian; LI Yan; GUO Ji-Hua; LI Jia-Qiang

    2001-01-01

    We demonstrate an approach to obtain the frequency differences from 1 MHz to hundreds of MHz including3-40 MHz, which was a blank range of the frequency difference in the traditional dual frequency lasers. Weemploy an intra-cavity stress birefringence element in an He-Ne laser, and at the same time apply a transversemagnetic field to the laser. The intra-cavity stress birefringence element, which is the window plate or the mirrorsubstrate applied by a force, is used to split a frequency into two; I.e. To make a single-frequency laser outputtingtwo frequencies. Moreover, the transverse magnetic field is used to decrease greatly the mode competition between the two frequencies so that they are able to oscillate simultaneously. The minimum value of magnetic field forefficiently eliminating the mode competition to ensure the two frequencies work together is studied experimentally.The power tuning performance of the two frequencies (o-light and e-light) is investigated.

  6. Photo-induced birefringence in optical fibres : a comparative study of low-bi and hi-bi fibres

    OpenAIRE

    Bardal, S.; Kamal, A; Russell, P. St. J.

    1992-01-01

    A study of photoinduced birefringence in bow-tie (stress-induced) high-birefringence (Hi-Bi) and low-birefringence (Lo-Bi) germanosilicate optical fibers is conducted by using 532-nm light. The study reveals that Hi-Bi fibers are insensitive to light polarized along the fast axis, in contrast to Lo-Bi fibers, which are photosensitive along both axes. The induced birefringence in Lo-Bi fibers is reversible, whereas the change in Hi-Bi fibers is permanent. The sign of the induced birefringence ...

  7. Single-mode fibre optic Bragg grating sensing on the base of birefringence in surface-mounting and embedding applications

    Science.gov (United States)

    Lee, Jung-Ryul; Tsuda, Hiroshi; Koo, Bon-Yong

    2007-02-01

    Birefringence effects in the two typical installation techniques of fibre Bragg grating(FBG) sensor are investigated: surface-mounting and embedding configurations. When the FBG is bonded on a host material, the sensitivity loss in ultrasonic measurement caused by glue-induced low-birefringence is first reported. Next, the transverse stress-induced high birefringence when the FBG is embedded into a fabric composite laminate is measured as 3.6×10 -4. Such induced-birefringence effects are experimentally analysed in mechanical applications. Simple and effective solutions with respect to the respective installation configurations for removing the birefringence effect are proposed and the obtained zero-birefringence cases are compared with the birefringent cases.

  8. Torsion nonminimally coupled to the electromagnetic field and birefringence

    CERN Document Server

    Rubilar, G F; Hehl, F W; Rubilar, Guillermo F.; Obukhov, Yuri N.; Hehl, Friedrich W.

    2003-01-01

    In conventional Maxwell--Lorentz electrodynamics, the propagation of light is influenced by the metric, not, however, by the possible presence of a torsion T. Still the light can feel torsion if the latter is coupled nonminimally to the electromagnetic field F by means of a supplementary Lagrangian of the type l^2 T^2 F^2 (l = coupling constant). Recently Preuss suggested a specific nonminimal term of this nature. We evaluate the spacetime relation of Preuss in the background of a general O(3)-symmetric torsion field and prove by specifying the optical metric of spacetime that this can yield birefringence in vacuum. Moreover, we show that the nonminimally coupled homogeneous and isotropic torsion field in a Friedmann cosmos affects the speed of light.

  9. Torsion nonminimally coupled to the electromagnetic field and birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Rubilar, Guillermo F [Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile); Obukhov, Yuri N [Institute for Theoretical Physics, University of Cologne, 50923 Cologne (Germany); Hehl, Friedrich W [Institute for Theoretical Physics, University of Cologne, 50923 Koeln (Germany)

    2003-07-21

    In conventional Maxwell-Lorentz electrodynamics, the propagation of light is influenced by the metric, not, however, by the possible presence of a torsion T. Still the light can feel torsion if the latter is coupled nonminimally to the electromagnetic field F by means of a supplementary Lagrangian of the type {approx}l{sup 2}T{sup 2}F{sup 2} (l = coupling constant). Recently Preuss suggested a specific nonminimal term of this nature. We evaluate the spacetime relation of Preuss in the background of a general O(3)-symmetric torsion field and prove by specifying the optical metric of spacetime that this can yield birefringence in vacuum. Moreover, we show that the nonminimally coupled homogeneous and isotropic torsion field in a Friedmann cosmos affects the speed of light. (letter to the editor)

  10. Birefringence effects of short probe pulses of electromagnetically induced transparency

    Science.gov (United States)

    Parshkov, Oleg M.; Kochetkova, Anastasia E.; Budyak, Victoria V.

    2016-04-01

    The numerical simulation results of radiations evolution in the presence of electromagnetically induced transparency for J=0-->J=1-->J=2 scheme of degenerate quantum transitions are presented. The pulse regime of wave interaction with Doppler broadening spectral lines was investigated. It was indicated that when the control field is linear polarized, the input circular polarized probe pulse breaks up in the medium into pulses with mutually perpendicular linear polarizations. Polarization direction of one of these pulses coincides with the polarization direction of control fields. The distance, which probe pulse passes in the medium to its full separation, decreases, when input probe pulse duration or control field intensity decreases. The input probe pulse intensity variation almost does not influence separation distance and speed of the linear polarized probe pulses in the medium. The effects, described above, may be interpreted as the birefringence effects of electromagnetically induced transparency in the case of short probe pulse.

  11. Investigations on birefringence effects in polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Hu, Xiaolian; Saez-Rodriguez, D.; Bang, Ole;

    2014-01-01

    Step-index polymer optical fiber Bragg gratings (POFBGs) and microstructured polymer optical fiber Bragg gratings (mPOFBGs) present several attractive features, especially for sensing purposes. In comparison to FBGs written in silica fibers, they are more sensitive to temperature and pressure...... because of the larger thermo-optic coefficient and smaller Young's modulus of polymer materials. (M)POFBGs are most often photowritten in poly(methylmethacrylate) (PMMA) materials using a continuous-wave 325 nm HeCd laser. For the first time to the best of our knowledge, we study photoinduced...... birefringence effects in (m)POFBGs. To achieve this, highly reflective gratings were inscribed with the phase mask technique. They were then monitored in transmission with polarized light. For this, (m)POF sections a few cm in length containing the gratings were glued to angled silica fibers. Polarization...

  12. Strong optical feedback in birefringent dual frequency laser

    Institute of Scientific and Technical Information of China (English)

    Mao Wei; Zhang Shu-Lian

    2006-01-01

    Strong optical feedback in a birefringent dual frequency He-Ne laser with a high reflectivity feedback mirror has been investigated for the first time. The output characteristics of two orthogonally polarized modes are demonstrated in two different optical feedback cases: one is for both modes being fed back and the other is for only one of the modes being fed back. Strong mode competition can be observed between the two modes with strong optical feedback. And when one mode's intensity is near its maximum, the other mode is nearly extinguished. When both modes are fed back into the laser cavity, the mode competition is stronger than when only one mode is fed back. The difference in initial intensity between the two orthogonally polarized modes plays an important role in the mode competition, which has been experimentally and theoretically demonstrated.

  13. Maxwell's field coupled nonminimally to quadratic torsion: Axion and birefringence

    International Nuclear Information System (INIS)

    We consider a possible (parity conserving) interaction between the electromagnetic field F and a torsion field Tα of spacetime. For generic elementary torsion, gauge invariant coupling terms of lowest order fall into two classes that are both nonminimal and quadratic in torsion and respect Maxwell's equations. The first class ∼FT2 admits F's without the presence of charges and is excluded. The second class ∼F2T2 modifies the constitutive tensor of spacetime and can also be completely described in the framework of metricfree electrodynamics. We recognize three physical effects of the torsion: (i) An axion field that induces an optical activity into spacetime, (ii) a modification of the light cone structure that yields birefringence, and (iii) a torsion dependence of the velocity of light. We study these effects in the background of a Friedmann universe with torsion

  14. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  15. Vacuum birefringence as a probe of Planck scale noncommutativity

    International Nuclear Information System (INIS)

    Because of ultraviolet/infrared (UV/IR) mixing, the low energy physics of noncommutative gauge theories in the Moyal-Weyl approach seems to depend crucially on the details of the ultraviolet completion. However, motivated by recent string theory analyses, we argue that their phenomenology with a very general class of UV completions can be accurately modelled by a cutoff close to the Planck scale. In the infrared the theory tends continuously to the commutative gauge theory. If the photon contains contributions from a trace-U(1), we would observe vacuum birefringence, i.e. a polarisation dependent propagation speed, as a residual effect of the noncommutativity. Constraints on this effect require the noncommutativity scale to be close to the Planck scale. (Orig.)

  16. Measurement of Birefringence of Low-Loss, High-Reflectance Coating of M-Axis Sapphire

    OpenAIRE

    Camp, Jordan B.; Kells, William; Fejer, Martin M.; Gustafson, Eric

    2001-01-01

    The birefringence of a low-loss, high-reflectance coating applied to an 8-cm-diameter sapphire crystal grown in the m-axis direction has been mapped. By monitoring the transmission of a high-finesse Fabry-Perot cavity as a function of the polarization of the input light, we find an upper limit for the magnitude of the birefringence of 2.5 x 10^-4 rad and an upper limit in the variation in direction of the birefringence of 10 deg. These values are sufficiently small to allow consideration of m...

  17. A Novel Edge Filter Demodulation Technique by Using High Birefringence Fiber Sagnac Loop Mirror

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel way of edge filter demodulation for fiber Bragg grating sensor is put forward. A high birefringence fiber Sagnac loop mirror is used as edge filter to demodulate FBG sensor wavelength shift in range of about 8 nm.

  18. On the birefringence of healthy and malaria-infected red blood cells

    CERN Document Server

    Dharmadhikari, Aditya K; Dharmadhikari, Jayashree A; Sharma, Shobhona; Mathur, Deepak

    2013-01-01

    We have probed how the birefringence of a healthy red blood cell (RBC) changes as it becomes infected by a malarial parasite. By analyzing the polarization properties of light transmitted through a single, optically-trapped cell we demarcate two types of birefringence: form birefringence which depends on the shape of the cell and intrinsic birefringence which is brought about by the presence of the parasite. We quantitatively measure changes in the refractive index as normal RBS become infected by a malarial parasite. Malarial infections are found to induce changes in the cell's refractive index whose magnitude depends on the stage of malarial infection; such changes were quantitatively explored and found to be large, in the range 1.2 to 3$\\times10^{-2}$. Our results have implications for the development and use of non-invasive techniques that seek to quantify changes in cell properties induced by pathological states accompanying diseases like malaria. From a broader prespective, information forthcoming from ...

  19. Spin-Hall effect and circular birefringence of a uniaxial crystal plate

    CERN Document Server

    Bliokh, K Y; Prajapati, C; Puentes, G; Viswanathan, N K; Nori, F

    2016-01-01

    The linear birefringence of uniaxial crystal plates is known since the 17th century. Here we demonstrate, both theoretically and experimentally, a fine lateral circular birefringence of such crystal plates. We show that this effect is a novel example of the spin-Hall effect of light, i.e., a transverse spin-dependent shift of the paraxial light beam transmitted through the plate. The well-known linear birefringence and the new circular birefringence form an interesting analogy with the Goos-Hanchen and Imbert-Fedorov beam shifts that appear in the light reflection at a dielectric interface. We report the experimental observation of the effect in a remarkably simple system of a tilted half-wave plate and polarizers using polarimetric and quantum-weak-measurement techniques for the beam-shift measurements.

  20. A strain-induced birefringent double-clad fiber Bragg grating

    Institute of Scientific and Technical Information of China (English)

    Lijun Li; Lei Sun; Wande Fan; Zhi Wang; Jianhua Luo; Shenggui Fu; Shuzhong Yuan; Xiaoyi Dong

    2005-01-01

    @@ A strain-induced birefringence double-clad (DC) fiber Bragg grating (FBG) is proposed and demonstrated.The grating is fabricated in the core of rectangular inner cladding double clad fiber by using phase mask method. By applying lateral strain on the grating, the birefringence is induced. In order to detect the birefringent effect of the grating, we use it as the output mirror of a laser. When lateral strain is applied,the grating becomes birefringent. Therefore, one reflection peak of double-clad fiber Bragg grating becomes two peaks and the laser also lases in two wavelengths. The wavelength spacing of the laser can be tuned from 0 to 0.8 nm. The absolute wavelengths for the two polarizations can be tuned 1.2 and 2.0 nm,respectively.

  1. Supercontinuum Generation with High Birefringence SF6 Soft Glass Photonic Crystal Fibers

    International Nuclear Information System (INIS)

    A kind of high birefringence SF6 soft glass photonic crystal fiber (HBSF6-PCF) is proposed. The properties of birefringence, dispersion, nonlinear coefficient and the transmission characteristics are studied by the multipole method and the adaptive split-step Fourier method. The numerical results show that the birefringence and the nonlinear coefficient reach the orders of 10-2 and 10-1, respectively. In addition, the HBSF6-PCFs can generate very smooth supercontinuum spectra when illuminated with femtosecond pulsed light of 1064 nm. It is found that up to 800 nm spectral width (evaluated at −5dB from the peak) is achieved. Therefore, the advantage of the HBSF6-PCFs is such that a high birefringence, a high nonlinearity and a smooth supercontinuum are perfectly combined in them. (fundamental areas of phenomenology (including applications))

  2. Analysis of a highly birefringent asymmetric photonic crystal fibre based on a surface plasmon resonance sensor

    Science.gov (United States)

    Liu, Chao; Wang, Famei; Zheng, Shijie; Sun, Tao; Lv, Jingwei; Liu, Qiang; Yang, Lin; Mu, Haiwei; Chu, Paul K.

    2016-07-01

    A highly birefringent photonic crystal fibre is proposed and characterized based on a surface plasmon resonance sensor. The birefringence of the sensor is numerically analyzed by the finite-element method. In the numerical simulation, the resonance wavelength can be directly positioned at this birefringence abrupt change point and the depth of the abrupt change of birefringence reflects the intensity of excited surface plasmon. Consequently, the novel approach can accurately locate the resonance peak of the system without analyzing the loss spectrum. Simulated average sensitivity is as high as 1131 nm/RIU, corresponding to a resolution of 1 × 10-4 RIU in this sensor. Therefore, results obtained via the approach not only show polarization independence and less noble metal consumption, but also reveal better performance in terms of accuracy and computation efficiency.

  3. In-situ measurement of vacuum window birefringence by atomic spectroscopy

    CERN Document Server

    Steffen, Andreas; Genske, Maximilian; Meschede, Dieter; Robens, Carsten; Alberti, Andrea

    2013-01-01

    We present an in-situ method to measure the birefringence of a single vacuum window by means of microwave spectroscopy on an ensemble of cold atoms. Stress-induced birefringence can cause an ellipticity in the polarization of an initially linearly-polarized laser beam. The amount of ellipticity can be reconstructed by measuring the differential vector light shift of an atomic hyperfine transition. Measuring the ellipticity as a function of the linear polarization angle allows us to infer the amount of birefringence $\\Delta n$ at the level of $10^{-8}$ and identify the orientation of the optical axes. The key benefit of this method is the ability to separately characterize each vacuum window, allowing the birefringence to be precisely compensated in existing vacuum apparatuses.

  4. Note: In situ measurement of vacuum window birefringence by atomic spectroscopy.

    Science.gov (United States)

    Steffen, Andreas; Alt, Wolfgang; Genske, Maximilian; Meschede, Dieter; Robens, Carsten; Alberti, Andrea

    2013-12-01

    We present an in situ method to measure the birefringence of a single vacuum window by means of microwave spectroscopy on an ensemble of cold atoms. Stress-induced birefringence can cause an ellipticity in the polarization of an initially linearly polarized laser beam. The amount of ellipticity can be reconstructed by measuring the differential vector light shift of an atomic hyperfine transition. Measuring the ellipticity as a function of the linear polarization angle allows us to infer the amount of birefringence Δn at the level of 10(-8) and identify the orientation of the optical axes. The key benefit of this method is the ability to separately characterize each vacuum window, allowing the birefringence to be precisely compensated in existing vacuum apparatuses. PMID:24387479

  5. Effects of Periodically Inhomogeneous Birefringence on Dark-Bright Vector Soliton Propagation and Interaction

    Institute of Scientific and Technical Information of China (English)

    LI Hong; D. N. Wang

    2007-01-01

    The effects of periodically inhomogeneous birefringence on dark-bright vector soliton propagation and interaction are investigated by the numerical method. The birefringence leads to the submergence of the dark soliton and the disintegration of the bright soliton, and enhances the interaction between the neighbouring solitons. The system performance is determined by the bright soliton because the dark soliton has robust features. Finally, the avoidance and the effective control are introduced, and the controlling mechanism is demonstrated.

  6. Tuning Characteristics of Frequency Difference for Zeeman-Birefringence He-Ne Dual Frequency Laser

    Institute of Scientific and Technical Information of China (English)

    肖岩; 张书练; 李岩; 朱钧

    2003-01-01

    Characteristics of frequency difference tuning of Zeeman-birefringence He-Ne dual frequency lasers (ZBDFLs) are explored. We design an automatic system of tuning cavity and power detection, which can tune the laser cavity and record the tuning curves of light power and frequency difference simultaneously. A synthetic phenomenon by Zeeman effect, mode pulling effect and birefringence effect is verified to exist in ZBDFLs. By analysing the tuning behaviour, this synthetic phenomenon is discovered and qualitatively explained for the first time.

  7. Electric-field-induced linear birefringence in TmAl3(BO3)4.

    Science.gov (United States)

    Pashchenko, M I; Bedarev, V A; Merenkov, D N; Gnatchenko, S L; Bezmaternykh, L N; Sukhachev, A L; Temerov, V L

    2016-04-20

    The linear birefringence induced by the electric field was first detected in a TmAl3(BO3)4 single crystal. The electric field dependence of the birefringence was investigated. The estimation of the electro-optical coefficient of the material gives ≈1.5×10-10  cm/V for a wavelength 632.8 nm. PMID:27140114

  8. Surface waves at the interface between left-handed and birefringent materials

    OpenAIRE

    Crasovan, Lucian-Cornel; Takayama, Osamu; Artigas, David; Johansen, Steffen Kjaer; Mihalache, Dumitru; Torner, Lluis

    2006-01-01

    We theoretically investigate the existence and properties of hybrid surface waves forming at interfaces between left-handed materials and dielectric birefringent media. The existence conditions of such waves are found to be highly relaxed in comparison to the original hybrid surface waves, discovered by Dyakonov, in configurations involving birefringent materials and right-handed media. Hybrid surface waves in left-handed materials feature remarkable properties: (i) a high degree of localizat...

  9. Scintillation detectors with multilayer polymer mirror reflector based on giant birefringent optics

    International Nuclear Information System (INIS)

    The design of interference mirrors is presented with unprecedented performance if birefringence is on the order of the change of the in-plane refractive index between adjacent polymeric layers (giant birefringent optics, GBO). Such a mirror, with ≥ 98% reflectivity in the visible, the VM2000 film was used to upgrade the performance of the DIAMANT charged particle detector system built up from CsI(Tl) scintillators coupled to Si-pin photodiodes. (R.P.)

  10. Accurate and quantitative polarization-sensitive OCT by unbiased birefringence estimator with noise-stochastic correction

    Science.gov (United States)

    Kasaragod, Deepa; Sugiyama, Satoshi; Ikuno, Yasushi; Alonso-Caneiro, David; Yamanari, Masahiro; Fukuda, Shinichi; Oshika, Tetsuro; Hong, Young-Joo; Li, En; Makita, Shuichi; Miura, Masahiro; Yasuno, Yoshiaki

    2016-03-01

    Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of OCT that contrasts the polarization properties of tissues. It has been applied to ophthalmology, cardiology, etc. Proper quantitative imaging is required for a widespread clinical utility. However, the conventional method of averaging to improve the signal to noise ratio (SNR) and the contrast of the phase retardation (or birefringence) images introduce a noise bias offset from the true value. This bias reduces the effectiveness of birefringence contrast for a quantitative study. Although coherent averaging of Jones matrix tomography has been widely utilized and has improved the image quality, the fundamental limitation of nonlinear dependency of phase retardation and birefringence to the SNR was not overcome. So the birefringence obtained by PS-OCT was still not accurate for a quantitative imaging. The nonlinear effect of SNR to phase retardation and birefringence measurement was previously formulated in detail for a Jones matrix OCT (JM-OCT) [1]. Based on this, we had developed a maximum a-posteriori (MAP) estimator and quantitative birefringence imaging was demonstrated [2]. However, this first version of estimator had a theoretical shortcoming. It did not take into account the stochastic nature of SNR of OCT signal. In this paper, we present an improved version of the MAP estimator which takes into account the stochastic property of SNR. This estimator uses a probability distribution function (PDF) of true local retardation, which is proportional to birefringence, under a specific set of measurements of the birefringence and SNR. The PDF was pre-computed by a Monte-Carlo (MC) simulation based on the mathematical model of JM-OCT before the measurement. A comparison between this new MAP estimator, our previous MAP estimator [2], and the standard mean estimator is presented. The comparisons are performed both by numerical simulation and in vivo measurements of anterior and

  11. Field anomaly of magnetic linear birefringence in magnetoelectric LiCoPO4

    Directory of Open Access Journals (Sweden)

    M.F. Kharchenko

    2000-09-01

    Full Text Available Investigations of the magnetic field induced linear and circular birefringence in the antiferromagnetic magnetoeleclric crystal LiCoPO4 were performed. A step-like change at H~20 kOe accompanied by magnetic hysteresis possessing high-field long tail was revealed. The behaviour of induced birefringence points to the magnetic field induced spin-reorientation phase transition to a non-collinear incommensurate structure.

  12. Quantification of birefringence readily measures the level of muscle damage in zebrafish

    International Nuclear Information System (INIS)

    Highlights: ► Report of an unbiased quantification of the birefringence of muscle of fish larvae. ► Quantification method readily identifies level of overall muscle damage. ► Compare zebrafish muscle mutants for level of phenotype severity. ► Proposed tool to survey treatments that aim to ameliorate muscular dystrophy. -- Abstract: Muscular dystrophies are a group of genetic disorders that progressively weaken and degenerate muscle. Many zebrafish models for human muscular dystrophies have been generated and analysed, including dystrophin-deficient zebrafish mutants dmd that model Duchenne Muscular Dystrophy. Under polarised light the zebrafish muscle can be detected as a bright area in an otherwise dark background. This light effect, called birefringence, results from the diffraction of polarised light through the pseudo-crystalline array of the muscle sarcomeres. Muscle damage, as seen in zebrafish models for muscular dystrophies, can readily be detected by a reduction in the birefringence. Therefore, birefringence is a very sensitive indicator of overall muscle integrity within larval zebrafish. Unbiased documentation of the birefringence followed by densitometric measurement enables the quantification of the birefringence of zebrafish larvae. Thereby, the overall level of muscle integrity can be detected, allowing the identification and categorisation of zebrafish muscle mutants. In addition, we propose that the establish protocol can be used to analyse treatments aimed at ameliorating dystrophic zebrafish models.

  13. Quantification of birefringence readily measures the level of muscle damage in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Joachim, E-mail: Joachim.Berger@Monash.edu [Australian Regenerative Medicine Institute, EMBL Australia, Monash University, Clayton (Australia); Sztal, Tamar; Currie, Peter D. [Australian Regenerative Medicine Institute, EMBL Australia, Monash University, Clayton (Australia)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer Report of an unbiased quantification of the birefringence of muscle of fish larvae. Black-Right-Pointing-Pointer Quantification method readily identifies level of overall muscle damage. Black-Right-Pointing-Pointer Compare zebrafish muscle mutants for level of phenotype severity. Black-Right-Pointing-Pointer Proposed tool to survey treatments that aim to ameliorate muscular dystrophy. -- Abstract: Muscular dystrophies are a group of genetic disorders that progressively weaken and degenerate muscle. Many zebrafish models for human muscular dystrophies have been generated and analysed, including dystrophin-deficient zebrafish mutants dmd that model Duchenne Muscular Dystrophy. Under polarised light the zebrafish muscle can be detected as a bright area in an otherwise dark background. This light effect, called birefringence, results from the diffraction of polarised light through the pseudo-crystalline array of the muscle sarcomeres. Muscle damage, as seen in zebrafish models for muscular dystrophies, can readily be detected by a reduction in the birefringence. Therefore, birefringence is a very sensitive indicator of overall muscle integrity within larval zebrafish. Unbiased documentation of the birefringence followed by densitometric measurement enables the quantification of the birefringence of zebrafish larvae. Thereby, the overall level of muscle integrity can be detected, allowing the identification and categorisation of zebrafish muscle mutants. In addition, we propose that the establish protocol can be used to analyse treatments aimed at ameliorating dystrophic zebrafish models.

  14. Characteristics of light polarization in magneto-optic fiber Bragg gratings with linear birefringence

    Institute of Scientific and Technical Information of China (English)

    Baojian Wu; Chongzhen Li; Kun Qiu; Liwei Cheng

    2011-01-01

    @@ The coupling between guided optical waves in magneto-optic fiber Bragg gratings (MFBGs) with linear birefringence is investigated using the eigen-mode and coupled-mode approaches. The relationship between the polarization-dependent loss (PDL) and the eigen states of polarization (SOPs) in the MFBGs is discussed. Only the MFBGs with low linear birefringence are applied to the peak PDL-based magnetic field measurement, after which the linear dynamic range is determined using the relative magnitude of linear and magnetically induced circular birefringence. In this letter, a theoretical model is presented to explain the experimental results and help develop novel MFBG-based devices.%The coupling between guided optical waves in magneto-optic fiber Bragg gratings (MFBGs) with linear birefringence is investigated using the eigen-mode and coupled-mode approaches. The relationship between the polarization-dependent loss (PDL) and the eigen states of polarization (SOPs) in the MFBGs is discussed. Only the MFBGs with low linear birefringence are applied to the peak PDL-based magnetic field measurement, after which the linear dynamic range is determined using the relative magnitude of linear and magnetically induced circular birefringence. In this letter, a theoretical model is presented to explain the experimental results and help develop novel MFBG-based devices.

  15. Glue-induced birefringence in surface-attached FBG strain sensors

    Science.gov (United States)

    Helminger, Dominik; Daitche, Alexej; Roths, Johannes

    2014-05-01

    The influence of the gluing process on the birefringence of surface-glued FBGs that were inscribed in highly birefringence (HiBi) optical fibers of type Panda was studied by monitoring the variation of the birefringence during the gluing procedure. The isothermal curing process at 100°C of the epoxy-based adhesive is characterized by the reduction of birefringence during curing. Significant transversal strain is introduced into the fiber during the cool down period, which is due to different thermal expansion coefficients of the silica and the glue. When the slow axis of the HiBi fiber is oriented parallel to the surface, the glue-induced transversal strain reduces the birefringence of the fiber by ΔB = -6.6 10-5 and when it is perpendicular to the surface, it is increased by ΔB = 1.1 10-5. It can be estimated that for conventional FBGs in single mode fibers a glue-induced birefringence in the order of ΔB = 3.4 10-5 can be expected, which has to be taken into account if in surface-mounted FBG-based strain measurements a high accuracy has to be achieved.

  16. PHOTOINDUCED BIREFRINGENCE AND NUMERICAL SOLUTION OF A NEW DYNAMIC MODEL IN AN AMORPHOUS COPOLYMER CONTAINING AZOBENZENE GROUPS

    Institute of Scientific and Technical Information of China (English)

    Ling-zhi Zhang; Zhi-gang Cai; Valerica Ninulescu; Ke Jin; Zhao-xi Liang

    2001-01-01

    Photoinduced birefringence is investigated in a new amorphous copolymer containing azobenzene groups. The levels of birefringence signal are found to depend on the polarization angle between the pump beam and the probe beam, and on the ellipticity of the pump beam. Both the growth and decay processes of the birefringence signal can be described by known biexponential equations. The rate constants and the amplitudes associated with the growth process of the photoinduced birefringence are observed to display a linear dependence with the pump beam intensity. A new dynamic model of the photoinduced birefringence is presented taking into account the contributions of both the trans and cis isomers ofazobenzene groups and the local polymer segments. The numerical treatment of this model shows good agreement with the experimental data in the whole writing-erasing processes of the photoinduced birefringence conducted in our polymer samples.

  17. Time Circular Birefringence in Time-Dependent Magnetoelectric Media

    CERN Document Server

    Zhang, Ruo-Yang; Lin, Shi-Rong; Zhao, Qing; Wen, Weijia; Ge, Mo-Lin

    2015-01-01

    Light traveling in time-dependent media has many extraordinary properties which can be utilized to convert frequency, achieve temporal cloaking, and simulate cosmological phenomena. In this paper, we focus on time-dependent axion-type magnetoelectric (ME) media, and prove that light in these media always has two degenerate modes with opposite circular polarizations corresponding to one wave vector $\\mathbf{k}$, and name this effect "time circular birefringence" (TCB). By interchanging the status of space and time, the pair of TCB modes can appear simultaneously via "time refraction" and "time reflection" of a linear polarized incident wave at a time interface of ME media. The superposition of the two TCB modes causes the "time Faraday effect", namely the globally unified polarization axes rotate with time. A circularly polarized Gaussian pulse traversing a time interface is also studied. If the wave-vector spectrum of a pulse mainly concentrates in the non-traveling-wave band, the pulse will be trapped with n...

  18. Validating Laser-Induced Birefringence Theory with Plasma Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Cecilia [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cornell Univ., Ithaca, NY (United States)

    2015-09-02

    Intense laser beams crossing paths in plasma is theorized to induce birefringence in the medium, resulting from density and refractive index modulations that affect the polarization of incoming light. The goal of the associated experiment, conducted on Janus at Lawrence Livermore’s Jupiter Laser Facility, was to create a tunable laser-plasma waveplate to verify the relationship between dephasing angle and beam intensity, plasma density, plasma temperature, and interaction length. Interferometry analysis of the plasma channel was performed to obtain a density map and to constrain temperature measured from Thomson scattering. Various analysis techniques, including Fast Fourier transform (FFT) and two variations of fringe-counting, were tried because interferograms captured in this experiment contained unusual features such as fringe discontinuity at channel edges, saddle points, and islands. The chosen method is flexible, semi-automated, and uses a fringe tracking algorithm on a reduced image of pre-traced synthetic fringes. Ultimately, a maximum dephasing angle of 49.6° was achieved using a 1200 μm interaction length, and the experimental results appear to agree with predictions.

  19. Analysis of birefringence in magneto-optical waveguides based on nanoparticles doped sol-gel matrix with an optimized substrate

    Science.gov (United States)

    Lebbal, M. R.; Boumaza, T.; Bouchemat, M.

    2015-01-01

    The elimination of birefringence remains a key challenge in integrated optical systems. In this work, we present birefringence study based on the controlling of layer thickness of planar waveguides, using deposited layers based on magnetic nanoparticles. The birefringence can be reduced with a planar device, depending on a glass substrate. The simulation carried out by MATLAB allowed us to deduce the conditions to decrease the phase mismatch and increase the conversion ratio of modes.

  20. Channelled spectrum method for birefringence dispersion measurement of anisotropic Mylar film

    Science.gov (United States)

    Sanaâ, F.; Palierne, J. F.; Gharbia, M.

    2016-07-01

    A convenient and accurate interferometric technique for measuring the birefringence dispersion of anisotropic Mylar film according to a continuous spectral range of wavelengths in the ultraviolet, visible and near infrared region, using the so called "Channelled Spectrum" method is described. The technique proposed here consists of considering all the experimental data, not only the minima of the transmitted light obtained after recording the transmitted light that travelled a Mylar film sandwiched between two crossed polarizers. Furthermore, we are able to measure the transmission coefficients of the polarizers, the absorption of the Mylar sheet, and other parameters involved in the experiment by using a spectroscopic detection. Thus, the transmission of the Mylar sheet vs wavelength is deduced. Using the dispersion of the optical birefringence given by the birefringence dispersion theory for uniaxial organic compounds ie the one band, three-band, and Cauchy models, and by applying a nonlinear fitting procedure on the recorded experimental data, we have obtained the parameters involved in the expressions of the optical birefringence and we have computed the optical birefringence of the Mylar film vs wavelengths. In the visible and near-infrared regions, all models give excellent fits to the experimental data. In the UV region, the three-band model considers the resonance effect. Thus, in the near-resonance region the results from the three-band model are more accurate.

  1. Birefringence imaging of posterior eye by multi-functional Jones matrix optical coherence tomography.

    Science.gov (United States)

    Sugiyama, Satoshi; Hong, Young-Joo; Kasaragod, Deepa; Makita, Shuichi; Uematsu, Sato; Ikuno, Yasushi; Miura, Masahiro; Yasuno, Yoshiaki

    2015-12-01

    A clinical grade prototype of posterior multifunctional Jones matrix optical coherence tomography (JM-OCT) is presented. This JM-OCT visualized depth-localized birefringence in addition to conventional cumulative phase retardation imaging through local Jones matrix analysis. In addition, it simultaneously provides a sensitivity enhanced scattering OCT, a quantitative polarization uniformity contrast, and OCT-based angiography. The probe beam is at 1-μm wavelength band. The measurement speed and the depth-resolution were 100,000 A-lines/s, and 6.6 μm in tissue, respectively. Normal and pathologic eyes are examined and several clinical features are revealed, which includes high birefringence in the choroid and lamina cribrosa, and birefringent layered structure of the sclera. The theoretical details of the depth-localized birefringence imaging and conventional phase retardation imaging are formulated. This formulation indicates that the birefringence imaging correctly measures a depth-localized single-trip phase retardation of a tissue, while the conventional phase retardation can provide correct single-trip phase retardation only for some specific types of samples. PMID:26713208

  2. Enhanced Transmission Stability of Polarization Solitons in Birefringent Fibres with an Optical Phase Conjugator

    Institute of Scientific and Technical Information of China (English)

    陈伟成; 谢嘉宁; 路洪; 徐文成

    2003-01-01

    An optical phase conjugator is used to enhance transmission stability of polarization solitons in highly birefringent fibres. Two polarization solitons form a breather in fibres with low birefringence firstly and the optical phase conjugator is used to make the spectra of polarization solitons converse, which results in the fact that the polarization soliton along the fast axis is compressed due to the strengthened self-phase modulation effect. Two polarization solitons are compressed further due to the cross-phase modulation effect. The enhanced nonlinear effects make the central peak frequencies of two polarization solitons shift to the larger range in opposite directions so that they trap each other fully to suppress the effect of birefringence.

  3. Temperature sensibility of the birefringence properties in side-hole photonic crystal fiber filled with Indium

    International Nuclear Information System (INIS)

    We report on the temperature sensitivity of the birefringence properties of a special kind of photonic crystal fiber containing two side holes filled with Indium metal. The modulation of the fiber birefringence is accomplished through the stress field induced by the expansion of the metal. Although the fiber was made at low gas pressures during the indium infiltration process, the birefringence showed anomalous property at a relatively low temperature value, which is completely different from those reported in conventional-like fibers with two holes filled with metal. By modeling the anisotropic changes induced by the metal expansion to the refractive index within the fiber, we are able to reproduce the experimental results. Our results have practical relevance for the design of devices based on this technology

  4. Temperature sensibility of the birefringence properties in side-hole photonic crystal fiber filled with Indium

    Energy Technology Data Exchange (ETDEWEB)

    Reyes-Vera, Erick, E-mail: erickreyes@itm.edu.co; Gómez-Cardona, Nelson D. [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840 Medellín (Colombia); Facultad de Ingeniería, Instituto Tecnológico Metropolitano, A.A. 54954 Medellín (Colombia); Chesini, Giancarlo; Cordeiro, Cristiano M. B. [Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas-UNICAMP, Campinas, SP (Brazil); Torres, Pedro [Escuela de Física, Universidad Nacional de Colombia, A.A. 3840 Medellín (Colombia)

    2014-11-17

    We report on the temperature sensitivity of the birefringence properties of a special kind of photonic crystal fiber containing two side holes filled with Indium metal. The modulation of the fiber birefringence is accomplished through the stress field induced by the expansion of the metal. Although the fiber was made at low gas pressures during the indium infiltration process, the birefringence showed anomalous property at a relatively low temperature value, which is completely different from those reported in conventional-like fibers with two holes filled with metal. By modeling the anisotropic changes induced by the metal expansion to the refractive index within the fiber, we are able to reproduce the experimental results. Our results have practical relevance for the design of devices based on this technology.

  5. Novel technique for distributed fibre sensing based on coherent Rayleigh scattering measurements of birefringence

    Science.gov (United States)

    Lu, Xin; Soto, Marcelo A.; Thévenaz, Luc

    2016-05-01

    A novel distributed fibre sensing technique is described and experimentally validated, based on birefringence measurements using coherent Rayleigh scattering. It natively provides distributed measurements of temperature and strain with more than an order of magnitude higher sensitivity than Brillouin sensing, and requiring access to a single fibre-end. Unlike the traditional Rayleigh-based coherent optical time-domain reflectometry, this new method provides absolute measurements of the measurand and may lead to a robust discrimination between temperature and strain in combination with another technique. Since birefringence is purposely induced in the fibre by design, large degrees of freedom are offered to optimize and scale the sensitivity to a given quantity. The technique has been validated in 2 radically different types of birefringent fibres - elliptical-core and Panda polarization-maintaining fibres - with a good repeatability.

  6. Cosmic birefringence fluctuations and cosmic microwave background B-mode polarization

    Directory of Open Access Journals (Sweden)

    Seokcheon Lee

    2015-06-01

    Full Text Available Recently, BICEP2 measurements of the cosmic microwave background (CMB B-mode polarization has indicated the presence of primordial gravitational waves at degree angular scales, inferring the tensor-to-scalar ratio of r=0.2 and a running scalar spectral index, provided that dust contamination is low. In this Letter, we show that the existence of the fluctuations of cosmological birefringence can give rise to CMB B-mode polarization that fits BICEP2 data with r<0.11 and no running of the scalar spectral index. When dust contribution is taken into account, we derive an upper limit on the cosmological birefringence, Aβ2<0.0075, where A is the amplitude of birefringence fluctuations that couple to electromagnetism with a coupling strength β.

  7. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    Science.gov (United States)

    Karbstein, Felix; Sundqvist, Chantal

    2016-07-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article, we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at an x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experiment.

  8. Effect of dimerization on the field-induced birefringence in ferrofluids.

    Science.gov (United States)

    Szczytko, Jacek; Vaupotič, Nataša; Osipov, Mihail A; Madrak, Karolina; Górecka, Ewa

    2013-06-01

    The magnetic-field-induced birefringence in a ferrofluid composed of spherical cobalt nanoparticles has been studied both experimentally and theoretically. The considerable induced birefringence determined experimentally has been attributed to the formation of chains of nanoparticles. The birefringence has been measured as a function of the external magnetic field and the volume fraction (f) of nanoparticles. It is quadratic in f as opposed to the Faraday effect, which is linear in f. Experimental results agree well with the theoretical model based on a simple density functional approach. For dilute solutions the experimental results can be explained by assuming that only dimers of nanoparticles are formed while the concentration of longer chains is negligible. PMID:23848690

  9. A promising birefringent crystal Ba2Na3(B3O6)2F

    Science.gov (United States)

    Wang, Xing; Xia, Mingjun; Li, R. K.

    2014-12-01

    Bulk crystals of Ba2Na3(B3O6)2F (BNBF) have been successfully grown by top-seeded solution growth (TSSG) technique. Its transmittance spectra show a wide transparency range from 186 nm to 3000 nm. The refractive indices in 13 wavelengths were measured with high accuracy and the Sellmeier equations were obtained, which demonstrated that the title crystal displayed a birefringence (Δn = 0.1030 at 588 nm) comparable to that of the commercial birefringent crystal α-BBO (the high temperature form of BaB2O4). A prototype Glan-Taylor polarizer made of BNBF prisms was fabricated, which showed high transparency and large optical extinction ratio similar to the commercial polarizer made of α-BBO. In addition, BNBF crystal is less moisture sensitive than that of α-BBO, thus BNBF can be a potential new birefringent crystal.

  10. Magnetic field fiber sensor based on the magneto-birefringence effect of magnetic fluid

    Science.gov (United States)

    Lei, Xueqin; Chen, Jiajia; Shi, Fuquan; Chen, Daru; Ren, Zhijun; Peng, Baojin

    2016-09-01

    In this study, the magneto-birefringence effect of magnetic fluid (MF) is adopted to form an innovative fiber optic magnetic field sensor. The sensitive section is fabricated via a D-shaped microstructure inscribed in a high-birefringence fiber Sagnac loop with a femtosecond laser. The D-shaped microstructure facilitates good combination of the optical-fiber Sagnac interferometer with the magneto-birefringence effect of MF without suffering from absorption loss and manual alignment. Experimental results show the good performance of the magnetic field fiver sensor, particularly its high stable extinction ratio. Preliminary results are provided, and the magnetic field sensitivity of 0.0823 nm/mT can be further improved by increasing the depth and length of the D-shaped microstructure.

  11. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    CERN Document Server

    Karbstein, Felix

    2016-01-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at a x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experim...

  12. Temperature dependence of birefringence in ethanol-filled suspended core fiber.

    Science.gov (United States)

    Vilas, Jose Luis; Sanchez-Martin, Jose Antonio; Bernabeu, Eusebio

    2016-08-10

    The temperature dependence of the birefringence in a suspended core fiber (SCF) has been experimentally analyzed by using a polarimetric setup. The used configuration consists of two linear polarizers and the SCF as birefringent medium. A theoretical study based on Jones matrices has been carried out to analyze the experimental observed behavior. For this, a polarimetric all-fiber configuration was used whose sensitivity depends on the wavelength variation with temperature. Results obtained show that it is strongly affected when the air holes of SCF are partially filled with ethanol. PMID:27534462

  13. Integrated optic polarization splitter based on total internal reflection from a birefringent polymer.

    Science.gov (United States)

    Huang, Guanghao; Park, Tae-Hyun; Chu, Woo-Sung; Oh, Min-Cheol

    2016-09-01

    An integrated optic polarization splitter with large fabrication tolerance and high reliability is required for optical signal processing in quantum-encrypted communication systems. A polarization splitter based on total internal reflection from a highly birefringent polymer-reactive mesogen-is proposed and demonstrated in this work. The device consists of a mode expander for reducing the wave vector distribution of the guided mode, and an interface with a large birefringence. Several polymers with suitable refractive indexes were used for fabricating the device. We obtained a polarization splitter with a low crosstalk (less than -30 dB), and a large fabrication tolerance. PMID:27607704

  14. Active polarisation control of a quantum cascade laser using tuneable birefringence in waveguides.

    Science.gov (United States)

    Dhirhe, D; Slight, T J; Holmes, B M; Ironside, C N

    2013-10-01

    We discuss the design, modelling, fabrication and characterisation of an integrated tuneable birefringent waveguide for quantum cascade lasers. We have fabricated quantum cascade lasers operating at wavelengths around 4450 nm that include polarisation mode converters and a differential phase shift section. We employed below laser threshold electroluminescence to investigate the single pass operation of the integrated device. We use a theory based on the electro-optic properties of birefringence in quantum cascade laser waveguides combined with a Jones matrix based description to gain an understanding of the electroluminescence results. With the quantum cascade lasers operating above threshold we demonstrated polarisation control of the output. PMID:24104336

  15. Correction of Birefringence and Thermal Lensing in Nonreciprocal Resonators by use of a Dynamic Imaging Mirror

    Science.gov (United States)

    Moshe, Inon; Jackel, Steven

    2000-08-01

    Enhanced correction of thermally induced birefringence in the presence of strong single-pass, azimuthally dependent bipolar focusing was achieved in single-rod laser oscillators by use of an adaptive optic rear mirror with image relay and aberration correction capabilities. Together with a Faraday rotator, the imaging variable radius mirror was successfully tested in stable and unstable Nd:Cr:GSGG power oscillators under variable pump power conditions from 0 to 800 W. Birefringence correction in the absence of ray retracing was achieved.

  16. ANALYSIS OF INDEXED-GUIDED HIGHLY BIREFRINGENT PHOTONIC CRYSTAL FIBER EMPLOYING DIFFERENT CLADDING GEOMETRIES

    Directory of Open Access Journals (Sweden)

    A. M. Jouri

    2015-07-01

    Full Text Available      In this paper, a comparative study of three geometries of highly birefringent photonic crystal fibers (HB PCF is presented. The proposed geometries are: V type PCF, Pseudo-Panda PCF and selectively liquid-filled PCF. Based on the famous Finite Difference Time Domain (FDTD method with the perfectly matched layer (PML boundary condition, the simulations are carried out in the aim to find a tradeoff between the chromatic dispersion, the birefringence and the confinement loss.

  17. The effect of vacuum birefringence on the polarization of X-ray binaries and pulsars

    Science.gov (United States)

    Novick, R.; Weisskopf, M. C.; Angel, J. R. P.; Sutherland, P. G.

    1977-01-01

    In a strong magnetic field the vacuum becomes birefringent. This effect is especially important for pulsars at X-ray wavelengths. Any polarized X-ray emission from the surface of a magnetic neutron star becomes depolarized as it propagates through the magnetic field. The soft X-ray emission from AM Her, believed to be a magnetic white dwarf, may show about one radian of phase retardation. In this case, circular polarization of the X-ray flux would be a characteristic signature of vacuum birefringence.

  18. Analysis of birefringence in magneto-optical waveguides based on nanoparticles doped sol–gel matrix with an optimized substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lebbal, M.R., E-mail: Lebbalmohamedredha@yahoo.fr; Boumaza, T.; Bouchemat, M.

    2015-01-01

    The elimination of birefringence remains a key challenge in integrated optical systems. In this work, we present birefringence study based on the controlling of layer thickness of planar waveguides, using deposited layers based on magnetic nanoparticles. The birefringence can be reduced with a planar device, depending on a glass substrate. The simulation carried out by MATLAB allowed us to deduce the conditions to decrease the phase mismatch and increase the conversion ratio of modes. - Highlights: • We simulate the birefringence in isotropic and anisotropic waveguides. • The perpendicularly applied gelation field is very promising in decreasing the birefringence. • It is very promising to use the glass substrate and adjust the thin layer thickness. • The glass substrate contributes in increasing the range of mono-mode waveguide. • The optimal thickness is taken close to the cut-off thickness of the 2nd mode TE.

  19. Analysis of birefringence in magneto-optical waveguides based on nanoparticles doped sol–gel matrix with an optimized substrate

    International Nuclear Information System (INIS)

    The elimination of birefringence remains a key challenge in integrated optical systems. In this work, we present birefringence study based on the controlling of layer thickness of planar waveguides, using deposited layers based on magnetic nanoparticles. The birefringence can be reduced with a planar device, depending on a glass substrate. The simulation carried out by MATLAB allowed us to deduce the conditions to decrease the phase mismatch and increase the conversion ratio of modes. - Highlights: • We simulate the birefringence in isotropic and anisotropic waveguides. • The perpendicularly applied gelation field is very promising in decreasing the birefringence. • It is very promising to use the glass substrate and adjust the thin layer thickness. • The glass substrate contributes in increasing the range of mono-mode waveguide. • The optimal thickness is taken close to the cut-off thickness of the 2nd mode TE

  20. LiTaO.sub.3./sub. crystals with near-zero birefringence

    Czech Academy of Sciences Publication Activity Database

    Glazier, A. M.; Zhang, N.; Bartasyte, A.; Keeble, D.S.; Huband, S.; Thomas, P.A.; Gregora, Ivan; Borodavka, Fedir; Margueron, S.; Hlinka, Jiří

    2012-01-01

    Roč. 45, č. 5 (2012), s. 1030-1037. ISSN 0021-8898 Institutional research plan: CEZ:AV0Z10100520 Keywords : lithium tantalate * birefringence * domains * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.343, year: 2012

  1. A novel high-birefringence fiber loop mirror electric current sensor

    Science.gov (United States)

    Bo, Dong; Zhao, Qida; Liao, Liubo Tongqing; Li, Shuhong; Zeng, Xiangye; Miao, Yinping; Huang, Guiling

    2007-11-01

    A novel electric current sensor based on a high-birefringence fiber loop mirror(HBFLM) and a kind of magnetostrictive material rod(MMR) is demonstrated theoretically and experimentally. Part of the high-birefringence fiber(HBF) is pasted onto the MMR which is placed in the central part of a solenoid. The HBFLM is used as the sensor head and the linear filter simultaneously. Part of the high-birefringence fiber(HBF) is pasted onto the MMR which is placed in the central part of a solenoid. The rod will have elastic lengthening along the direction of the magnetic field when the uniform magnetic field changes, which will lead to a change of transmission intensity of the HBFLM filter, thus the variation of the electric current can be determined via the laser wavelength within the quasi-linear transmission range of the HBFLM filter. The sensitivity reaches 0.0153/100mA, the resolution reaches 10mA. Comparing with the previous fiber-optic electric current sensor, it has nothing with the linear birefringence based on Faraday effects in the previous fiber-optic electric current sensor. Comparing with the expensive and complex FBG electric current, the sensing signal can be directly detected by a photodiode(PD) and complicated demodulation devices are avoidable. The advantages of the electric current include optical power detection, simple and smart structure, high sensitivity, low cost, and good repeatability, etc.

  2. Polarization modulational instability in a birefringent optical fiber with fourth order dispersion

    Indian Academy of Sciences (India)

    R Ganapathy; V C Kuriakose

    2001-10-01

    We obtain conditions for the occurrence of polarization modulational instability in the anomalous and normal dispersion regimes for the coupled nonlinear Schrödinger equation modelling fourth order dispersion effects when the linearly polarized pump is oriented at arbitrary angles with respect to the slow and fast axes of the birefringent fiber.

  3. Advancement in polarimetric glucose sensing: simulation and measurement of birefringence properties of cornea

    Science.gov (United States)

    Malik, Bilal H.; Coté, Gerard L.

    2011-03-01

    Clinical guidelines dictate that frequent blood glucose monitoring in diabetic patients is critical towards proper management of the disease. Although, several different types of glucose monitors are now commercially available, most of these devices are invasive, thereby adversely affecting patient compliance. To this end, optical polarimetric glucose sensing through the eye has been proposed as a potential noninvasive means to aid in the control of diabetes. Arguably, the most critical and limiting factor towards successful application of such a technique is the time varying corneal birefringence due to eye motion artifact. We present a spatially variant uniaxial eye model to serve as a tool towards better understanding of the cornea's birefringence properties. The simulations show that index-unmatched coupling of light is spatially limited to a smaller range when compared to the index-matched situation. Polarimetric measurements on rabbits' eyes indicate relative agreement between the modeled and experimental values of corneal birefringence. In addition, the observed rotation in the plane of polarized light for multiple wavelengths demonstrates the potential for using a dual-wavelength polarimetric approach to overcome the noise due to timevarying corneal birefringence. These results will ultimately aid us in the development of an appropriate eye coupling mechanism for in vivo polarimetric glucose measurements.

  4. Time-reversal-violating birefringence of photon in a medium exposed to electric and magnetic field

    OpenAIRE

    Baryshevsky, V. G.

    2013-01-01

    The T-reversal-violating optical gyrotropy is discussed. An expression for dielectric permittivity describing T-reversal-violating phenomena in a medium exposed to external electric and magnetic fields is presented. Optical phenomena of birefringence and polarization plane rotation of photon in a medium exposed to external electric and magnetic fields are considered.

  5. The measurement system of birefringence and Verdet constant of optical fiber

    Science.gov (United States)

    Huang, Yi; Chen, Li; Guo, Qiang; Pang, Fufei; Wen, Jianxiang; Shang, Yana; Wang, Tingyun

    2013-12-01

    The Faraday magneto-optical effect of optical fiber has many applications in monitoring magnetic field and electric current. When a linearly polarized light propagates in the direction of a magnetic field, the plane of polarization will rotate linearly proportional to the strength of the applied magnetic field, which following the relationship of θF =VBl. θF is the Faraday rotation angle, which is proportional to the magnetic flux density B and the Verdet constant V . However, when the optical fiber contains the effect of linear birefringence, the detection of Faraday rotation angle will depend on the line birefringence. In order to determine the Verdet constant of an optical fiber under a linear birefringence, the fiber birefringence needs to be accurately measured. In this work, a model is applied to analyze the polarization properties of an optical fiber by using the Jones matrix method. A measurement system based on the lock-in amplifier technology is designed to test the Verdet constant and the birefringence of optical fiber. The magnetic field is produced by a solenoid with a DC current. A tunable laser is intensity modulated with a motorized rotating chopper. The actuator supplies a signal as the phase-locked synchronization reference to the signal of the lock-in amplifier. The measurement accuracy is analyzed and the sensitivity of the system is optimized. In this measurement system, the Verdet constant of the SMF-28 fiber was measured to be 0.56±0.02 rad/T·m at 1550nm. This setup is well suitable for measuring the high signal-to-noise ratio (SNR) sensitivity for lock-in amplifier at a low magnetic field strength.

  6. Spacing-adjustable and wavelength-tunable multiwavelength fibre laser with nonlinear Brillouin gain and birefringence fibre loop mirror

    International Nuclear Information System (INIS)

    This paper demonstrates a room-temperature multiwavelength fibre laser with spacing-adjustability and wavelength-tunability. The nonlinear gain of self-excited stimulated Brillouin scattering can suppress mode competition induced by homogeneous broadening of Erbium-doped fibre. With the use of a birefringence fibre loop filter, the wavelength spacing can be adjusted by changing the length of the used birefringence fibre, and the lasing wavelengths can be finely tuned through modifying the filtering profile of the birefringence filter. Multiwavelength output with spectral spacing as small as 0.076 nm and a wavelength number of more than 80 has been successfully produced. (classical areas of phenomenology)

  7. External-cavity birefringence feedback effects of microchip Nd:YAG laser and its application in angle measurement

    International Nuclear Information System (INIS)

    External-cavity birefringence feedback effects of the microchip Nd: YAG laser are presented. When a birefringence element is placed in the external feedback cavity of the laser, two orthogonally polarized laser beams with a phase difference are output. The phase difference is twice as large as the phase retardation in the external cavity along the two orthogonal directions. The variable extra-cavity birefringence, caused by rotation of the external-cavity birefringence element, results in tunable phase difference between the two orthogonally polarized beams. This means that the roll angle information has been translated to phase difference of two output laser beams. A theoretical analysis based on the Fabry–Perot cavity equivalent model and refractive index ellipsoid is presented, which is in good agreement with the experimental results. This phenomenon has potential applications for roll angle measurement. (classical areas of phenomenology)

  8. SANS, SAXS, rheology and birefringence-strengths and weaknesses in probing phase behaviour of a diblock copolymer

    DEFF Research Database (Denmark)

    Vigild, Martin Etchells; Eskimergen, Rüya; Mortensen, Kell

    2004-01-01

    Asymmetrically composed diblock copolymers exhibit multiphase behaviour and transit the lamellae, gyroid and hexagonal cylindrical phases before reaching the order–disorder temperature, TODT. During a heating experiment towards TODT we observe that birefringence measurements are more sensitive th...

  9. SANS, SAXS, rheology and birefringence-strengths and weaknesses in probing phase behaviour of a diblock copolymer

    DEFF Research Database (Denmark)

    Vigild, Martin Etchells; Eskimergen, Rüya; Mortensen, Kell

    Asymmetrically composed diblock copolymers exhibit multiphase behaviour and transit the lamellae, gyroid and hexagonal cylindrical phases before reaching the order–disorder temperature, TODT. During a heating experiment towards TODT we observe that birefringence measurements are more sensitive th...... dynamic mechanical testing and have faster data acquisition rates than SANS when used to follow transient states of the sample. However, birefringence measurements cannot alone identify the precise phase behaviour....

  10. 3-D TECATE/BREW: Thermal, stress, and birefringent ray-tracing codes for solid-state laser design

    International Nuclear Information System (INIS)

    This report describes the physics, code formulations, and numerics that are used in the TECATE (totally Eulerian code for anisotropic thermo-elasticity) and BREW (birefringent ray-tracing of electromagnetic waves) codes for laser design. These codes resolve thermal, stress, and birefringent optical effects in 3-D stationary solid-state systems. This suite of three constituent codes is a package referred to as LASRPAK

  11. Wave propagation in birefringent materials with off axis absorption or gain

    CERN Document Server

    Sabooni, Mahmood; Kristensson, Gerhard; Rippe, Lars

    2016-01-01

    The polarization direction of an electromagnetic field changes and eventually reaches a steady state when propagating through a birefringent material with off axis absorption or gain. The steady state orientation direction depends on the magnitude of the absorption (gain) and the phase retardation rate. The change in the polarization direction is experimentally demonstrated in weakly doped ($0.05\\%$) Pr$^{3+}$:Y$_2$SiO$_5$ crystals, where the light polarization, if initially aligned along the most strongly absorbing principal axis, gradually switch to a much less absorbing polarization state during the propagation. This means that the absorption coefficient, $\\alpha$, in birefringent materials generally varies with length. This is important for, e.g., laser crystal gain media, highly absorbing and narrow band spectral filters and quantum memories.

  12. Real-time imaging of action potentials in nerves using changes in birefringence.

    Science.gov (United States)

    Badreddine, Ali H; Jordan, Tomas; Bigio, Irving J

    2016-05-01

    Polarized light can be used to measure the electrical activity associated with action potential propagation in nerves, as manifested in simultaneous dynamic changes in their intrinsic optical birefringence. These signals may serve as a tool for minimally invasive neuroimaging in various types of neuroscience research, including the study of neuronal activation patterns with high spatiotemporal resolution. A fast linear photodiode array was used to image propagating action potentials in an excised portion of the lobster walking leg nerve. We show that the crossed-polarized signal (XPS) can be reliably imaged over a ≥2 cm span in our custom nerve chamber, by averaging multiple-stimulation signals, and also in single-scan real-time "movies". This demonstration paves the way toward utilizing changes in the optical birefringence to image more complex neuronal activity in nerve fibers and other organized neuronal tissue. PMID:27231635

  13. Three-parameter error analysis method based on rotating coordinates in rotating birefringent polarizer system

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Junjie; Jia, Hongzhi, E-mail: hzjia@usst.edu.cn [Engineering Research Center of Optical Instruments and Systems, Ministry of Education, Shanghai Key Laboratory of Modern Optical Systems, School of Optical-electrical and Computer Engineering, University of Shanghai for Science and Technology, No. 516 JunGong Road, Shanghai 200093 (China)

    2015-11-15

    We propose error analysis using a rotating coordinate system with three parameters of linearly polarized light—incidence angle, azimuth angle on the front surface, and angle between the incidence and vibration planes—and demonstrate the method on a rotating birefringent prism system. The transmittance and angles are calculated plane-by-plane using a birefringence ellipsoid model and the final transmitted intensity equation is deduced. The effects of oblique incidence, light interference, beam convergence, and misalignment of the rotation and prism axes are discussed. We simulate the entire error model using MATLAB and conduct experiments based on a built polarimeter. The simulation and experimental results are consistent and demonstrate the rationality and validity of this method.

  14. Detecting relic gravitational waves in the CMB: The contamination caused by the cosmological birefringence

    Directory of Open Access Journals (Sweden)

    Wen Zhao

    2014-10-01

    Full Text Available The B-mode polarization of the cosmic microwave background (CMB radiation is an excellent information channel for the detection of relic gravitational waves. However, the detection is contaminated by the B-mode polarization generated by some other effects. In this paper, we discuss the contaminations caused by the cosmological birefringence, which converts the CMB E-mode to the B-mode, and forms the effective noise for the detection of gravitational waves. We find that this contamination is significant, if the rotation angle is large. However, this kind of B-mode can be properly de-rotated, and the effective noises can be greatly reduced. We find that, comparing with the contaminations caused by cosmic weak lensing, the residual polarization generated by the cosmological birefringence is negligible for the detection of relic gravitational waves in the CMB.

  15. Detecting relic gravitational waves in the CMB: The contamination caused by the cosmological birefringence

    International Nuclear Information System (INIS)

    The B-mode polarization of the cosmic microwave background (CMB) radiation is an excellent information channel for the detection of relic gravitational waves. However, the detection is contaminated by the B-mode polarization generated by some other effects. In this paper, we discuss the contaminations caused by the cosmological birefringence, which converts the CMB E-mode to the B-mode, and forms the effective noise for the detection of gravitational waves. We find that this contamination is significant, if the rotation angle is large. However, this kind of B-mode can be properly de-rotated, and the effective noises can be greatly reduced. We find that, comparing with the contaminations caused by cosmic weak lensing, the residual polarization generated by the cosmological birefringence is negligible for the detection of relic gravitational waves in the CMB

  16. Polarization-maintaining fiber pulse compressor by birefringent hollow-core photonic bandgap fiber.

    Science.gov (United States)

    Shirakawa, Akira; Tanisho, Motoyuki; Ueda, Ken-Ichi

    2006-12-11

    Structural birefringent properties of a hollow-core photonic-bandgap fiber were carefully investigated and applied to all-fiber chirped-pulse amplification as a compressor. The group birefringence of as high as 6.9x10(-4) and the dispersion splitting by as large as 149 ps/nm/km between the two principal polarization modes were observed at 1557 nm. By launching the amplifier output to one of the polarization modes a 17-dB polarization extinction ratio was obtained without any pulse degradation originating from polarization-mode dispersion. A hybrid fiber stretcher effectively compensates the peculiar dispersion of the photonic-bandgap fiber and pedestal-free 440-fs pulses with a 1-W average power and 21-nJ pulse energy were obtained. Polarization-maintaining fiber-pigtail output of high-power femtosecond pulses is useful for various applications. PMID:19529631

  17. Three-parameter error analysis method based on rotating coordinates in rotating birefringent polarizer system

    International Nuclear Information System (INIS)

    We propose error analysis using a rotating coordinate system with three parameters of linearly polarized light—incidence angle, azimuth angle on the front surface, and angle between the incidence and vibration planes—and demonstrate the method on a rotating birefringent prism system. The transmittance and angles are calculated plane-by-plane using a birefringence ellipsoid model and the final transmitted intensity equation is deduced. The effects of oblique incidence, light interference, beam convergence, and misalignment of the rotation and prism axes are discussed. We simulate the entire error model using MATLAB and conduct experiments based on a built polarimeter. The simulation and experimental results are consistent and demonstrate the rationality and validity of this method

  18. Simulation of birefringence effects on the dominant transversal laser resonator mode caused by anisotropic crystals.

    Science.gov (United States)

    Asoubar, Daniel; Zhang, Site; Wyrowski, Frank

    2015-06-01

    Birefringence effects can have a significant influence on the polarization state as well as on the transversal mode structure of laser resonators. This work introduces a flexible, fast and fully vectorial algorithm for the analysis of resonators containing homogeneous, anisotropic optical components. It is based on a generalization of the Fox and Li algorithm by field tracing, enabling the calculation of the dominant transversal resonator eigenmode. For the simulation of light propagation through the anisotropic media, a fast Fourier Transformation (FFT) based angular spectrum of plane waves approach is introduced. Besides birefringence effects, this technique includes intra-crystal diffraction and interface refraction at crystal surfaces. The combination with numerically efficient eigenvalue solvers, namely vector extrapolation methods, ensures the fast convergence of the method. Furthermore a numerical example is presented which is in good agreement to experimental measurements. PMID:26072756

  19. Detecting relic gravitational waves in the CMB: The contamination caused by the cosmological birefringence

    CERN Document Server

    Zhao, Wen

    2014-01-01

    The B-mode polarization of the cosmic microwave background (CMB) radiation is an excellent information channel for the detection of relic gravitational waves. However, the detection is contaminated by the B-mode polarization generated by some other effects. In this paper, we discuss the contaminations caused by the cosmological birefringence, which converts the CMB E-mode to the B-mode, and forms the effective noise for the detection of gravitational waves. We find that this contamination is significant, if the rotation angle is large. However, this kind of B-mode can be properly de-rotated, and the effective noises can be greatly reduced. We find that, comparing with the contaminations caused by cosmic weak lensing, the residual polarization generated by the cosmological birefringence is negligible for the detection of relic gravitational waves in the CMB.

  20. Nonlinear temperature dependence of glue-induced birefringence in polarization maintaining FBG sensors

    Science.gov (United States)

    Hopf, Barbara; Koch, Alexander W.; Roths, Johannes

    2016-05-01

    Glue-induced stresses decrease the accuracy of surface-mounted fiber Bragg gratings (FBG). Significant temperature dependent glue-induced birefringence was verified when a thermally cured epoxy-based bonding technique had been used. Determining the peak separation of two azimuthally aligned FBGs in PM fibers combined with a polarization resolved measurement set-up in a temperature range between -30°C and 150°C revealed high glue-induced stresses at low temperatures. Peak separations of about 60 pm and a nonlinear temperature dependence of the glue-induced birefringence due to stress relaxation processes and a visco-elastic behavior of the used adhesive have been shown.

  1. A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion.

    Science.gov (United States)

    Cukras, Janusz; Kauczor, Joanna; Norman, Patrick; Rizzo, Antonio; Rikken, Geert L J A; Coriani, Sonia

    2016-05-21

    A computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree-Fock and time-dependent density functional theory. Magneto-chiral dichroism and magneto-chiral birefringence spectra in the (resonant) frequency region below the first ionization threshold of R-methyloxirane and l-alanine are presented and compared with the corresponding results obtained for both the electronic circular dichroism and the magnetic circular dichroism. The additional information content yielded by the magneto-chiral phenomena, as well as their potential experimental detectability for the selected species, is discussed. PMID:27118603

  2. A note on the birefringence angle estimation in CMB data analysis

    Science.gov (United States)

    Gruppuso, A.; Maggio, G.; Molinari, D.; Natoli, P.

    2016-05-01

    Parity violating physics beyond the standard model of particle physics induces a rotation of the linear polarization of photons. This effect, also known as cosmological birefringence (CB), can be tested with the observations of the cosmic microwave background (CMB) anisotropies which are linearly polarized at the level of 5–10%. In particular CB produces non-null CMB cross correlations between temperature and B mode-polarization, and between E- and B-mode polarization. Here we study the properties of the so called D-estimators, often used to constrain such an effect. After deriving the framework of both frequentist and Bayesian analysis, we discuss the interplay between birefringence and weak-lensing, which, albeit parity conserving, modifies pre-existing TB and EB cross correlation.

  3. A note on the birefringence angle estimation in CMB data analysis

    CERN Document Server

    Gruppuso, Alessandro; Molinari, Diego; Natoli, Paolo

    2016-01-01

    Parity violating physics beyond the standard model of particle physics induces a rotation of the linear polarization of photons. This effect, also known as cosmological birefringence (CB), can be tested with the observations of the cosmic microwave background (CMB) anisotropies which are linearly polarized at the level of $5-10\\%$. In particular CB produces non-null CMB cross correlations between temperature and B mode-polarization, and between E- and B-mode polarization. Here we study the properties of the so called D-estimators, often used to constrain such an effect. After deriving the framework of both frequentist and Bayesian analysis, we discuss the interplay between birefringence and weak-lensing, which, albeit parity conserving, modifies pre-existing TB and EB cross correlation.

  4. Distributed strain measurement using modal interference in a birefringent optical fiber

    International Nuclear Information System (INIS)

    We propose a method based on modal interference in a birefringent optical fiber for distributed strain measurement. A frequency-modulated optical signal from a laser diode was launched in a birefringent fiber whose 'V' number was set in the range 2.405–3.831. The beat signal produced due to the interference of two lower order modes LP01 and LP11 was detected in a photodetector. The change in propagation constants between two modes under loading conditions leads to a phase variation of interference signal. The amplitude of the beat frequency was measured in the frequency domain by varying the modulating frequency, and it provides the measurand distribution along the beam. Results for strain distribution of a simply supported beam (51.0 cm × 3.0 cm × 0.6 cm) for an applied load of 250–1500 g are presented

  5. Cross-phase-modulation-instability band gap in a birefringence-engineered photonic-crystal fiber

    Science.gov (United States)

    Kibler, B.; Amrani, F.; Morin, P.; Kudlinski, A.

    2016-01-01

    We report the cancellation of the cross-phase-modulation-instability (XPMI) gain over a large spectral window (which we term the XPMI band gap) in a highly birefringent photonic-crystal fiber with zero group birefringence. The XPMI ceases to occur when single-frequency pumping of orthogonally polarized modes takes place in such a spectral band gap whose frequency bandwidth depends on the pump power itself. The suppression of XPMI sidebands is confirmed experimentally when Raman scattering remains negligible. At high powers the Raman Stokes wave, generated by the pump, implies novel dual-frequency pump configurations with large group-velocity mismatch, thus leading to another type of Raman-induced XPMI sidebands. The experimental results are in good agreement with analytical phase-matching calculations and numerical simulations.

  6. Suppression of Soliton Timing Jitters in Fibers with Random Birefringence by Periodical Polarization Modulation

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-cheng; XU Wen-cheng

    2006-01-01

    Periodical polarization modulation scheme is proposed to suppress timing jitters induced by frequency fluctuations between two polarization components of solitons. In periodical polarization modulation scheme, the polarization states of the soliton are modulated to excite equally for suppressing timing jitters induced by two unequal polarization components in the soliton trapping. Moreover, polarization modulation can weaken the effect of random birefringence on the soliton pulses in each relay distance. The numerical result shows that the soliton timing jitters are suppressed by our proposed method.

  7. Dispersion-managed soliton interactions in fibers with randomly varying birefringence

    Institute of Scientific and Technical Information of China (English)

    蔡炬; 杨祥林

    2003-01-01

    In this paper, a soliton transmission model in high-speed dispersion-managed systems is advanced, and the equation of intrachannel soliton interactions in randomly varying birefringent fibers is acquired. The soliton interactions with the impact of PMD in uniform dispersion systems and DMS systems are also investigated numerically. We reveal the change in the collision length with PMD and map strength, and verify the robustness of DMS to PMD in soliton interactions.

  8. Thermal distortion and birefringence in repetition-rate plasma electrode Pockels cell for high average power

    Institute of Scientific and Technical Information of China (English)

    Dingxiang Cao; Xiongjun Zhang; Wanguo Zheng; Shaobo He; Zhan Sui

    2007-01-01

    We numerically study thermally induced birefringence and distortion in plasma electrode Pockels cell based on KD*P as the electro-optic material. This device can repetitively operate under the heat capacity mode.Simulation results indicate that the excellent switching performances and low wave-front distortion are achieved within several tens seconds working time at average power in excess of 1 kW.

  9. Experimental study of polarization properties of highly birefringent photonic crystal fibers

    OpenAIRE

    Ritari, T.; Ludvigsen, H.; Wegmuller, Mark; Legre, Matthieu; Gisin, Nicolas; Folkenberg, J. R.; Nielsen, M D

    2004-01-01

    We analyze experimentally the polarization properties of highly nonlinear small-core photonic crystal fibers (PCFs) with no intentional birefringence. The properties of recently emerged polarization maintaining PANDA PCFs are also investigated. The wavelength and temperature dependence of phase and group delay of these fibers are examined in the telecommunications wavelength range. Compared to a standard PANDA fiber, the polarization characteristics and temperature dependence are found to be ...

  10. Influence of Feedback Levels on Polarized Optical Feedback Characteristics in Zeeman-Birefringence Dual Frequency Lasers

    Institute of Scientific and Technical Information of China (English)

    MAO Wei; ZHANG Shu-Lian; ZHOU Lu-Fei; LIU Xiao-Yan; WANG Ming-Ming

    2007-01-01

    The influence of Feedback levels on the intensity and polarization properties of polarized optical feedback in a Zeeman-birefringence dual frequency laser is systematically investigated. By changing the feedback power ratio, different feedback levels are obtained. Three distinct regimes of polarized optical feedback effects are found and defined as regimes Ⅰ, Ⅱand Ⅲ. The feedback level boundaries among the regimes are acquired experimentally. The theoretical analysis is presented to be in good agreement with the experimental results.

  11. Imaging of irradiated human costal cartilage birefringence by PS-OCT

    Energy Technology Data Exchange (ETDEWEB)

    Martinho Junior, Antonio C.; Freitas, Anderson Z.; Santin, Stefany P.; Soares, Fernando A.N.; Mosca, Rodrigo C.; Bringel, Fabiana A.; Mathor, Monica B., E-mail: freitas.az@ipen.b, E-mail: rmosca@usp.b, E-mail: mathor@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Sterilization by ionizing radiation is a technique used for tissue banks around the world to avoid transmission of infectious diseases by human allografts. However, high doses of ionizing radiation may cause undesirable changes in tissue structure, decreasing its mechanical properties, for example. Optical Coherence Tomography (OCT) is a non destructive, non ionizing and real time method to investigate biological tissues without promote any change in tissue structure. Polarization Sensitive Optical Coherence Tomography (PS-OCT) is an OCT technique that combines polarimetry with low coherence reflectometry to provide depth resolved measurements from birefringent structures as collagen. Costal cartilages from 15 cadaveric donors were preserved in high concentration glycerol and each individual sample was divided in 6 fragments. One of them was kept as a control group and the others were irradiated with gamma radiation from a Co-60 source with doses of 15, 25, 50, 75 and 100 kGy. OCT and PS-OCT images of the same region of the samples were obtained from a device OCS 1300 SS (Thorlabs, USA) with a coupling polarization module PSOCT 1300 (Thorlabs, USA). According with our results, birefringence may be visualized in all test groups as well in the control group, suggesting that sterilization by ionizing radiation does not affect the collagen structure significantly to cause total loss of birefringence, even if high doses as 75 and 100 kGy are used. The next step of our work is to develop a new method to quantify the birefringence using the optical properties of the tissue. (author)

  12. Functional birefringent elements imprinted by femtosecond laser nanostructuring of multi-component glass

    OpenAIRE

    Beresna, M.; R. Drevinskas; Lipatiev, A.S.; Fedotov, S.S.; Lotarev, S.V.; Sigaev, V.N.; Kazansky, P. G.

    2015-01-01

    A decade ago, a new type of self-organization process was observed in the bulk of SiO2 glass after irradiation with ultrashort laser pulses [1]. Under certain irradiation conditions, highly ordered nanostructures with features smaller than 20 nm could be formed in the irradiated volume. The sub-wavelength arrangement of these structures results in form birefringence, which was recently exploited for demonstrating a variety of functional optical elements in silica glass [2]. Despite excellent ...

  13. Imaging of irradiated human costal cartilage birefringence by PS-OCT

    International Nuclear Information System (INIS)

    Sterilization by ionizing radiation is a technique used for tissue banks around the world to avoid transmission of infectious diseases by human allografts. However, high doses of ionizing radiation may cause undesirable changes in tissue structure, decreasing its mechanical properties, for example. Optical Coherence Tomography (OCT) is a non destructive, non ionizing and real time method to investigate biological tissues without promote any change in tissue structure. Polarization Sensitive Optical Coherence Tomography (PS-OCT) is an OCT technique that combines polarimetry with low coherence reflectometry to provide depth resolved measurements from birefringent structures as collagen. Costal cartilages from 15 cadaveric donors were preserved in high concentration glycerol and each individual sample was divided in 6 fragments. One of them was kept as a control group and the others were irradiated with gamma radiation from a Co-60 source with doses of 15, 25, 50, 75 and 100 kGy. OCT and PS-OCT images of the same region of the samples were obtained from a device OCS 1300 SS (Thorlabs, USA) with a coupling polarization module PSOCT 1300 (Thorlabs, USA). According with our results, birefringence may be visualized in all test groups as well in the control group, suggesting that sterilization by ionizing radiation does not affect the collagen structure significantly to cause total loss of birefringence, even if high doses as 75 and 100 kGy are used. The next step of our work is to develop a new method to quantify the birefringence using the optical properties of the tissue. (author)

  14. Enhanced photoinduced birefringence in polymer-dye complexes: Hydrogen bonding makes a difference

    OpenAIRE

    Priimagi, Arri; Kaivola, Matti; Rodriguez, Francisco J.; Kauranen, Martti

    2007-01-01

    The authors demonstrate that photoinduced birefringence in azo-dye-doped polymers is strongly enhanced by hydrogen bonding between the guest molecules and the polymer host. The primary mechanism behind the enhancement is the possibility to use high dye doping levels compared to conventional guest-host systems because dye aggregation is restrained by hydrogen bonding. Moreover, hydrogen bonding reduces the mobility of the guest molecules in the polymer host leading to a larger fraction of the ...

  15. Semiconductor laser with a birefringent external cavity for information systems with wavelength division multiplexing

    Energy Technology Data Exchange (ETDEWEB)

    Paranin, V D; Matyunin, S A; Tukmakov, K N [S.P. Korolev Samara State Aerospace University, Samara (Russian Federation)

    2013-10-31

    The spectrum of a semiconductor laser with a birefringent external Gires – Tournois cavity is studied. The generation of two main laser modes corresponding to the ordinary and extraordinary wave resonances is found. It is shown that the radiation spectrum is controlled with a high energy efficiency without losses for spectral filtration. The possibility of using two-mode lasing in optical communication systems with wavelength division multiplexing is shown. (control of laser radiation parameters)

  16. Suppression and Enhancement of Soliton Switching During Interaction in Periodically Twisted Birefringent Fiber

    OpenAIRE

    Radhakrishnan, R; Lakshmanan, M

    1999-01-01

    Soliton interaction in periodically twisted birefringent optical fibers has been analysed analytically with refernce to soliton switching. For this purpose we construct the exact general two-soliton solution of the associated coupled system and investigate its asymptotic behaviour. Using the results of our analytical approach we point out that the interaction can be used as a switch to suppress or to enhance soliton switching dynamics, if one injects multi-soliton as an input pulse in the per...

  17. A diffusion approximation theorem for a nonlinear PDE with application to random birefringent optical fibers

    CERN Document Server

    Gazeau, Maxime

    2011-01-01

    In this article, we propose a generalization of the theory of diffusion approximation for random ODE to a nonlinear system of random Schr\\"odinger equations. This system arises in the study of pulse propagation in randomly birefringent optical fibers. We first show existence and uniqueness of solutions for the random PDE and the limiting equation. We follow the work of Garnier-Marty, where a linear electric field is considered, and we get an asymptotic dynamic for the nonlinear electric field.

  18. A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion

    DEFF Research Database (Denmark)

    Cukras, Janusz; Kauczor, Joanna; Norman, Patrick;

    2016-01-01

    A computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree–Fock and time-dependent density functional th...... circular dichroism. The additional information content yielded by the magneto-chiral phenomena, as well as their potential experimental detectability for the selected species, is discussed....

  19. FARADAY PLASMA CURRENT SENSOR WITH COMPENSATION FOR RECIPROCAL BIREFRINGENCE INDUCED BY MECHANICALPERTURBATIONS

    Directory of Open Access Journals (Sweden)

    Y. O. Barmenkov

    2003-07-01

    Full Text Available A Faraday fiber-optic current sensor was employed to measure the tokamak plasma current. In order todecrease the influence of mechanical perturbations on the sensor sensitivity, a two-pass optical scheme witha variable Faraday mirror at the fiber end is proposed. A decrease, by two orders of magnitude, in theinfluence of the linear birefringence produced by an external piezoceramic fiber modulator was experimentallyobserved.

  20. Bragg Gratings Induced in Birefringent Optical Fiber with an Elliptical Stress Cladding

    Directory of Open Access Journals (Sweden)

    I. K. Meshkovskiy

    2013-01-01

    Full Text Available The paper presents the results of writing of type I and high-performance type II fiber Bragg gratings in birefringent optical fiber with an elliptical stress cladding by a single 20 ns pulse of KrF excimer laser (248 nm. The gratings’ efficiency produced by a single pulse was up to 100%. Experimental results on visualization of these gratings are presented.

  1. Generating polarization-entangled photon pairs using cross-spliced birefringent fibers

    OpenAIRE

    Meyer-Scott, Evan; Van Roy, Vincent; Bourgoin, Jean-Philippe; Higgins, Brendon L.; Shalm, Lynden K.; Jennewein, Thomas

    2012-01-01

    We demonstrate a novel polarization-entangled photon-pair source based on standard birefringent polarization-maintaining optical fiber. The source consists of two stretches of fiber spliced together with perpendicular polarization axes, and has the potential to be fully fiber-based, with all bulk optics replaced with in-fiber equivalents. By modelling the temporal walk-off in the fibers, we implement compensation necessary for the photon creation processes in the two stretches of fiber to be ...

  2. Determination of Polydispersity of Magnetics Colloidal Nanopaticles by Optical Methods: Birefringence and Light Scattering Experiments

    Directory of Open Access Journals (Sweden)

    C.V. Yerin

    2014-07-01

    Full Text Available Determination of particle size distribution of the magnetic colloids according to the static and dynamic light scattering and magnetic birefringence were produced. Shown that the magnetic colloids with a low concentration of the solid phase are characterized by steady bimodal distribution, including individual nanoparticles with a size of 10-20 nm and aggregates of particles with a size of 40-80 nm.

  3. Transient magnetic birefringence for determining magnetic nanoparticle diameters in dense, highly light scattering media

    Science.gov (United States)

    Köber, Mariana; Moros, Maria; Grazú, Valeria; de la Fuente, Jesus M.; Luna, Mónica; Briones, Fernando

    2012-04-01

    The increasing use of biofunctionalized magnetic nanoparticles in biomedical applications calls for further development of characterization tools that allow for determining the interactions of the nanoparticles with the biological medium in situ. In cell-incubating conditions, for example, nanoparticles may aggregate and serum proteins adsorb on the particles, altering the nanoparticles’ performance and their interaction with cell membranes. In this work we show that the aggregation of spherical magnetite nanoparticles can be detected with high sensitivity in dense, highly light scattering media by making use of magnetically induced birefringence. Moreover, the hydrodynamic particle diameter distribution of anisometric nanoparticle aggregates can be determined directly in these media by monitoring the relaxation time of the magnetically induced birefringence. As a proof of concept, we performed measurements on nanoparticles included in an agarose gel, which scatters light in a similar way as a more complex biological medium but where particle-matrix interactions are weak. Magnetite nanoparticles were separated by agarose gel electrophoresis and the hydrodynamic diameter distribution was determined in situ. For the different particle functionalizations and agarose concentrations tested, we could show that gel electrophoresis did not yield a complete separation of monomers and small aggregates, and that the electrophoretic mobility of the aggregates decreased linearly with the hydrodynamic diameter. Furthermore, the rotational particle diffusion was not clearly affected by nanoparticle-gel interactions. The possibility to detect nanoparticle aggregates and their hydrodynamic diameters in complex scattering media like cell tissue makes transient magnetic birefringence an interesting technique for biological applications.

  4. Transient magnetic birefringence for determining magnetic nanoparticle diameters in dense, highly light scattering media

    International Nuclear Information System (INIS)

    The increasing use of biofunctionalized magnetic nanoparticles in biomedical applications calls for further development of characterization tools that allow for determining the interactions of the nanoparticles with the biological medium in situ. In cell-incubating conditions, for example, nanoparticles may aggregate and serum proteins adsorb on the particles, altering the nanoparticles’ performance and their interaction with cell membranes. In this work we show that the aggregation of spherical magnetite nanoparticles can be detected with high sensitivity in dense, highly light scattering media by making use of magnetically induced birefringence. Moreover, the hydrodynamic particle diameter distribution of anisometric nanoparticle aggregates can be determined directly in these media by monitoring the relaxation time of the magnetically induced birefringence. As a proof of concept, we performed measurements on nanoparticles included in an agarose gel, which scatters light in a similar way as a more complex biological medium but where particle–matrix interactions are weak. Magnetite nanoparticles were separated by agarose gel electrophoresis and the hydrodynamic diameter distribution was determined in situ. For the different particle functionalizations and agarose concentrations tested, we could show that gel electrophoresis did not yield a complete separation of monomers and small aggregates, and that the electrophoretic mobility of the aggregates decreased linearly with the hydrodynamic diameter. Furthermore, the rotational particle diffusion was not clearly affected by nanoparticle–gel interactions. The possibility to detect nanoparticle aggregates and their hydrodynamic diameters in complex scattering media like cell tissue makes transient magnetic birefringence an interesting technique for biological applications. (paper)

  5. Complex stress intensity factors at cracks in birefringent plates by the method of reflected caustics

    International Nuclear Information System (INIS)

    The optical method of reflected caustics was used for evaluating the stress intensity factors in cracked plates made of birefringent materials in the general case when the crack is submitted to a combined mode I and mode II deformations. It has been already shown that the reflected rays from the rear face of the transparent optically active material form a double caustic due to this optical anisotropy of the material and, on the other hand, it is also known that when a crack in an optically inert material is submitted to a combined mode I and mode II deformation the respective caustic is angularly displaced. In this paper the combined effect of the optical anisotropy of the material together with the general case of loading of the cracked plate defined by the ratio μ = Ksub(II)/Ksub(I), where Ksub(I,II) are the respective SIF's for either mode of deformation was studied. Nomograms for the exact evaluation of the respective stress intensity factors Ksub(I) and Ksub(II) from the geometric characteristics of both branches of the caustic for a series of birefringent materials and for different values of μ are given. A series of experiments with cracked birefringent plates made of polycarbonate with a coefficient of anisotropy xi sub(r) = 0.153 for different orientations of the crack have shown that the determination of Ksub(I) and Ksub(II) by these nomograms is accurate since there is a coincidence between theory and experiments. (orig.)

  6. Application of field-modulated birefringence and light scattering to biosensing

    Science.gov (United States)

    Strong, Louis H.; Hall, Daniel B.; Edson, Clark M.; Nguyen, Hiep-hoa; Whitt, Michael A.; Varadi, Gyula

    2011-03-01

    Superparamagnetic nanoparticles (NPs) coated with surface ligands are shown to be an effective means to impart magnetic field modulation to optical signals from targeted receptor complexes. The modulated signals they produce can be used for a number of important high throughput applications in bio-sensing including: detecting (weaponized) viruses, screening recombinant libraries of proteins, identifying pathogenic conversions of microbes, and monitoring gene amplification. We compare the results of two dynamic methods of measuring target binding to NPs: birefringence and field modulated light scattering (FMLS). These measurements reflect complementary manifestations of NP alignment (orientation) and de-alignment (relaxation) dynamics. Birefringence originates from the specific crystalline properties of a small subset of paramagnetic NPs (for example, maghemite) when oriented in a magnetic field. Upon quenching the field, it decays at a rate exhibiting the Debye-Stokes-Einstein rotational relaxation constant of target-NP complexes. Birefringence relaxation reflects the particle dynamics of the mixed suspension of NPs, with signal components weighted in proportion to the free and complexed NP size distributions. FMLS relaxation signals, on the other hand, originate predominately from the inherent optical anisotropy of the target complexes, show little contribution from non-complexed NPs when the targets are more optically anisotropic than the NPs, and provide a more direct and accurate method for determining target receptor concentrations. Several illustrations of the broad range of applications possible using these dynamic measurements and the kind of information to be derived from each detection modality will be discussed.

  7. Photon pair generation by intermodal spontaneous four wave mixing in birefringent, weakly guiding optical fibers

    CERN Document Server

    Garay-Palmett, K; Dominguez-Serna, F; Ortiz-Ricardo, E; Monroy-Ruz, J; Ramirez, H Cruz; Ramirez-Alarcon, R; U'Ren, A B

    2016-01-01

    We present a theoretical and experimental study of the generation of photon pairs through the process of spontaneous four wave mixing (SFWM) in a few-mode, birefringent fiber. Under these conditions, multiple SFWM processes are in fact possible, each associated with a different combination of transverse modes for the four waves involved. We show that in the weakly guiding regime, for which the propagation modes may be well approximated by linearly polarized modes, the departure from circular symmetry due to the fiber birefringence translates into conservation rules which retain elements from azimuthal and rectangular symmetries: both OAM and parity must be conserved for a process to be viable. We have implemented a SFWM source based on a "bow-tie" birefringent fiber, and have measured for a collection of pump wavelengths the SFWM spectra of each of the signal and idler photons in coincidence with its partner photon. We have used this information, together with knowledge of the transverse modes into which the ...

  8. Supercontinuum Generation in Photonic Crystal Fibers Possessing High Birefringence and Large Optical Nonlinearity

    CERN Document Server

    Sharma, Mohit; Konar, S

    2015-01-01

    This paper presents the design of an index guided highly birefringent photonic crystal fiber which promises to yield very large birefringence ~3.33 X 10^(-2) at 1550 nm and ~1.75 X 10^(-2) at 1064 nm as well as large effective nonlinearity ~80 W^(-1)km^(-1). Optical supercontinuum generation in the proposed fiber using a 1064 nm pump source with peak power of 1kW has been also presented. Finite difference time domain method (FDTD) has been employed to examine the optical properties such as fiber birefringence, mode field, V-parameter, walk-off and optical nonlinearity, while the Split-step Fourier method is used to solve the nonlinear Schrodinger equation felicitating the study of supercontinuum generation. Simulation results indicate that horizontal input pulse yields superior continuum in comparison to that of the vertically polarized input. However, the broadening of the continuum is about 1450 nm in case of horizontally polarized input light whereas it is approximately 2350 nm for vertically polarized.

  9. Digital Beam Steering Device Based on Decoupled Birefringent Prism Deflector and Polarization Rotator

    Science.gov (United States)

    Pishnyak, Oleg; Kreminska, Lyubov; Laventovich, Oleg D.; Pouch, John J.; Miranda, Felix A.; Winker, Bruce K.

    2004-01-01

    We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises a polarization rotator and a birefringent prism deflector. The birefringent prism deflects the beam by an angle that depends on polarization of the incident beam. The prism can be made of the uniaxial smectic A (SmA) liquid crystal (LC) or a solid crystal such as yttrium orthovanadate (YVO4). SmA prisms have high birefringence and can be constructed in a variety of shapes, including single prisms and prismatic blazed gratings of different angles and profiles. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by an electrically switched twisted nematic (TN) cell. A DBD composed of N rotator-deflector pairs steers the beam into 2(sup N) directions. As an example, we describe a four-stage DBD deflecting normally incident laser beam within the range of +/- 56 mrad with 8 mrad steps. Redirection of the beam is achieved by switching the TN cells.

  10. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, Maria, E-mail: mfr@fct.unl.pt; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Ferreira, Quirina [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Instituto de Telecomunicações, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Botelho do Rego, Ana Maria [Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa (Portugal)

    2015-09-21

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior.

  11. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    Science.gov (United States)

    Raposo, Maria; Ferreira, Quirina; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A.; do Rego, Ana Maria Botelho

    2015-09-01

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior.

  12. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    International Nuclear Information System (INIS)

    Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior

  13. Flow-induced birefringence measurement system using dual-crystal transverse electro-optic modulator for microgravity fluid physics applications

    Science.gov (United States)

    Mackey, Jeffrey R.

    1999-01-01

    We have developed a new instrument that can measure fast transient birefringence and polymer chain orientation angle in complex fluids. The instrument uses a dual-crystal transverse electro-optic modulator with the second crystal's modulation voltage applied 180 deg out of phase from that of the first crystal. In this manner, the second crystal compensates for the intrinsic static birefringence of the first crystal, and it doubles the modulation depth. By incorporating a transverse electro-optic modulator with two lithium-niobate (LiNbO3) crystals oriented orthogonal to each other with a custom-designed optical system, we have produced a very small robust instrument capable of fast transient retardation measurements. By measuring the sample thickness or optical path length through the sample, we can calculate the transient birefringence. This system can also measure dichroism. We have compared the calibration results and retardation and orientation angle measurements of this instrument with those of a photoelastic modulator (PEM) based system using a quarter wave plate and a high-precision 1/16-wave plate to simulate a birefringent sample. Transient birefringence measurements on the order of 10(exp -9) can be measured using either modulator.

  14. STUDY OF BIREFRINGENCE INFLUENCE ON IMAGE QUALITY OF PHOTOLITHOGRAPHY SYSTEMS IN VIEW OF PARTIALLY-COHERENT LIGHT SOURCE

    Directory of Open Access Journals (Sweden)

    E. A. Nikulina

    2015-03-01

    Full Text Available Subject of study. A vector model for conversion of electromagnetic radiation in optical systems is considered, taking into account the influence of birefringence, as well as partially coherent illumination. Model. The proposed model is based on the representation of the complex amplitude of the monochromatic field through thesuperposition of basic plane waves. Transmitted light image with partially coherent illumination is performed by the sourceintegration method. Main results. The results of simulation for the point spread function are demonstrating the level of the birefringence influence on the image quality. In the presence of the wave aberration about 0.098 of the wavelength, the wave energy loss in the center of the Airy disk with an average birefringence of 4 nm/cm was 8%, and at 16 nm/cm it reached 30%. The calculation of the point spread function for a real sample of fluorite is given. The central peak of the PSF without birefringence was 0.722, with regard to birefringence it was equal to 0.701. Practical significance. The findings can be used in the development of photolithographic lenses, as well as for the manufacturing of any other optical systems that require consideration of the polarization properties of the materials.

  15. Influences of temperature and transport properties on the birefringence of CdGeAs2

    Science.gov (United States)

    Fischer, D. W.; Ohmer, M. C.; McCrae, J. E.

    1997-04-01

    We have directly measured the birefringence Δn of CdGeAs2 using polarized light interference spectra obtained in transmittance from 2.4 to 18 μm over a temperature range of 14-450 K. Four different samples, exhibiting a wide range of free carrier concentrations, were studied. It was found that free carriers can have a significant effect on the room-temperature birefringence. At 14 K, however, the data from all samples were virtually identical. The temperature dependence of Δn was obtained from a sample with low carrier concentration (≈1015/cm3) and high resistivity (9 Ω cm). Its temperature derivative d(Δn)/dT was determined at 50 K increments over the entire 14-450 K temperature range, and was found to vary from 2.6×10-5/K at 100 K to 5.1×10-5/K at 400 K. A least-squares fit to the data yielded a temperature coefficient for Δn of 8.2×10-8/K. Hall-effect measurements indicate that the resistivity, mobility, and carrier concentration all exhibit a significant temperature dependence. The resistivity for one sample increased by a factor of 108 when cooled from room temperature to 14 K. Our results suggest that previously published Δn values were probably obtained from samples with relatively high carrier concentrations, and that our results more accurately describe the true intrinsic birefringence of the material. The value of Δn decreases by 0.0004 per 1016 carriers a factor of 10 less than suggested by theory but still significantly large. The heavy to light hole effective mass ratio in the uppermost valence band was found to be 7.1.

  16. Extensional viscosity and birefringence measurements of viscoelastic polymer solutions in filament stretching flows

    Energy Technology Data Exchange (ETDEWEB)

    Spiegelberg, S.H.; McKinley, G.H. [Harvard Univ., Cambridge, MA (United States)

    1996-12-31

    The evolution of the transient extensional stresses in dilute and semi-dilute viscoelastic polymer solutions are measured with a filament stretching rheometer of a design similar to that first introduced by Sridhar et al. (1991). The solutions are polystyrene-based (PS) Boger fluids that are stretched at constant strain rates ranging from 0.6 {le} {var_epsilon}{sub 0} {le} 4 s{sup -1} and to Hencky strains of {var_epsilon} > 4. The test fluids all strain-hardening and Trouton ratios exceeding 1000 are obtained at high strains. Experimental data exhibit strain-hardening at lower strain levels than predicted by bead-spring and FENE dumbbell models. We also monitor the decay of the tensile viscoelastic stress difference in the fluid filament following cessation of uniaxial elongation as a function of the total imposed Hencky strain and the strain rate. The extensional stresses initially decay very rapidly upon cessation of uniaxial elongation, and this drop in stress is followed by a slower viscoelastic relaxation. The measurements at moderate strains deviate significantly from the predictions of nonlinear dumbbell models. Flow induced birefringence measurements performed during elongation yield insight into the deformation-dependent conformation of the polymer chains. Tests are conducted in a neutral density fluid to prevent gravitational sagging that would be prevalent for the large sample diameters used in this study. The results demonstrate a monotonic rise in birefringence from {delta}n{prime} = 10{sup -8} to 10{sup -4} for samples stretched to Hencky strains of {var_epsilon} = 5. Newtonian samples stretched to the same levels demonstrate no rise in birefringence. The stress-optical law appears to fail at strains {var_epsilon} > 3 and the principal tensile stress difference compute from the relationship {delta}{tau} = {delta}n{prime}/C is significantly lower than the directly-measured stress difference.

  17. Soliton-dark pulse pair formation in birefringent cavity fiber lasers through cross phase coupling.

    Science.gov (United States)

    Shao, Guodong; Song, Yufeng; Zhao, Luming; Shen, Deyuan; Tang, Dingyuan

    2015-10-01

    We report on the experimental observation of soliton-dark pulse pair formation in a birefringent cavity fiber laser. Temporal cavity solitons are formed in one polarization mode of the cavity. It is observed that associated with each of the cavity solitons a dark pulse is induced on the CW background of the orthogonal polarization mode. We show that the dark pulse formation is a result of the incoherent cross polarization coupling between the soliton and the CW beam and has a mechanism similar to that of the polarization domain formation observed in the fiber lasers. PMID:26480138

  18. Generalized Morse wavelet for the determination of the birefringence of a liquid crystal cell

    International Nuclear Information System (INIS)

    The generalized Morse wavelet (GMW) was improved as an alternative tool to determine the birefringence dispersion of a liquid crystal (LC) material by using the transmittance spectrum. The GMW has two degrees of freedom and the advantage of this additional degree of freedom was clearly exhibited in the simulation study. The validity of the presented method was shown by using the transmittance spectrum of the ZLI-6000 coded nematic LC and the acquired results were compared with the results of other methods. The noise immunity and uncertainty of the presented method were also studied. (paper)

  19. Numerical analysis of stress distribution in embedded highly birefringent PANDA fibers

    Science.gov (United States)

    Lesiak, Piotr; Woliński, Tomasz

    2015-09-01

    The paper presents numerical analysis compared with experimental data of influence of polymerization shrinkage on highly birefringent (HB) PANDA optical fibers embedded in a composite material. Since polymerization is a chemical process consisting in combining single molecules in a macromolecular compound [1], principal directions of the polymerization shrinkage depend on a number of the composite layers associated with this process. In this paper a detailed analysis of the piezo-optic effects occurring in HB optical fibers before and after the lamination process answers the question to what extent a degree of the material degradation can be properly estimated.

  20. Degree of polarization fading of light passing through birefringent medium with optical axis variation

    Science.gov (United States)

    Makowski, Piotr L.; Domański, Andrzej W.

    2010-09-01

    Numerical implementation of Mueller-Stokes matrix calculus for polychromatic light is used to analyze and plainly illustrate polarization properties of multi-section linearly birefringent systems illuminated by the light of any spectrum profile. Numerical investigations are preceded by a detailed review of known concepts for modeling the depolarization phenomenon in anisotropic media. The numerical study examines efficiency of the Lyot depolarizer system undergoing variations from the optimal configuration. In addition, the power spectrum density profile and intrinsic polarization state of light passing through the system are considered as interesting degrees of freedom. The comparative analysis makes use of the degree of polarization and the depolarization index diagrams.

  1. Repeating Pulsed Magnet System for Axion-like Particle Searches and Vacuum Birefringence Experiments

    CERN Document Server

    Yamazaki, T; Namba, T; Asai, S; Kobayashi, T; Matsuo, A; Kindo, K; Nojiri, H

    2016-01-01

    We have developed a repeating pulsed magnet system which generates magnetic fields of about 10 T in a direction transverse to an incident beam over a length of 0.8 m with a repetition rate of 0.2 Hz. Its repetition rate is by two orders of magnitude higher than usual pulsed magnets. It is composed of four low resistance racetrack coils and a 30 kJ transportable capacitor bank as a power supply. The system aims at axion-like particle searches with a pulsed light source and vacuum birefringence measurements. We report on the details of the system and its performances.

  2. Direct UV written planar Bragg gratings that feature zero fluence induced birefringence

    Science.gov (United States)

    Holmes, Christopher; Cooper, Peter A.; Fernando, Harendra N. J.; Stroll, Andreas; Gates, James C.; Krishnan, Chirenjeevi; Haynes, Roger; Mennea, Paolo L.; Carpenter, Lewis G.; Gawith, Corin B. E.; Roth, Martin M.; Charlton, Martin D.; Smith, Peter G. R.

    2015-12-01

    Direct UV writing is a planar fabrication process capable of simultaneously defining waveguides and Bragg gratings. The technique is fully computer controlled and uniquely uses a small focused spot ~7 μm in diameter for direct writing exposure. This work investigates its use to achieve phase trimming and Bragg grating definition in silica-on-silicon lithographic waveguides. It is observed that birefringence control using direct UV writing can be made independent of exposure fluence with this technique through tailoring substrate stress. The result is demonstrated experimentally and supported theoretically using finite element analysis.

  3. Enhanced performance of semiconductor optical amplifier at high direct modulation speed with birefringent fiber loop

    Directory of Open Access Journals (Sweden)

    K. E. Zoiros

    2014-07-01

    Full Text Available We employ a birefringent fiber loop (BFL for enhancing the performance of a semiconductor optical amplifier (SOA which is directly modulated. By properly exploiting the BFL comb-like spectral response, we show that the SOA can be directly modulated at a data rate which is more than five times faster than that enabled by the SOA electrical bandwidth. The experimental results, which include chirp measurements, demonstrate the significant improvements achieved in the performance of the directly modulated SOA with the help of the BFL.

  4. Pump Spectral Bandwidth, Birefringence, and Entanglement in Type-II Parametric Down Conversion

    Directory of Open Access Journals (Sweden)

    Daniel Erenso

    2009-01-01

    Full Text Available The twin photons produced by a type-II spontaneous parametric down conversion are well know as a potential source of photons for quantum teleportation due to the strong entanglement in polarization. This strong entanglement in polarization, however, depends on the spectral composition of the pump photon and the nature of optical isotropy of the crystal. By exact numerical calculation of the concurrence, we have shown that how pump photons spectral width and the birefringence nature of the crystal directly affect the degree of polarization entanglement of the twin photons.

  5. Single negative birefringence in stacked spoof plasmon metasurfaces by prism experiment.

    Science.gov (United States)

    Beruete, M; Navarro-Cía, M; Falcone, F; Campillo, I; Sorolla, M

    2010-03-01

    We report negative and positive refraction in a prism made of stacked perforated thin surfaces for s and p polarization, respectively. By corrugating the subwavelength slits of a free-standing periodic arrangement, geometrically induced surface-plasmon-like currents are excited and transmission is allowed under s polarization (electric-field vector parallel to the slit). When several of those corrugated slit arrays are subwavelength stacked, the stack behaves as a negative effective index medium (because of double negativity) under s polarization, whereas it behaves as a positive effective index medium under p polarization. The birefringence has been confirmed by the usual wedge experiment in the millimeter-wave range. PMID:20195305

  6. Photoinduced Birefringence and Broadband All-Optical Photonic Switch in a Bacteriorhodopsin/Polymer Composite Film

    Institute of Scientific and Technical Information of China (English)

    WEI Lai; TENG Xue-Lei; Lu Ming; ZHAO You-Yuan; MA De-Wang; DING Jian-Dong

    2007-01-01

    Photoinduced birefringence with large optical nonlinearity in a bacteriorhodopsin/polymer composite film is observed.A high refractive index change of 8.5×10-5 photoinduced by 476nm pumping beam is reached at the low intensity of 6.5mW/cm2.Based on it,a broadband all-optical photonic switch is realized with an optical controlling switch system.Because of controlling beam's selectivity in switching,the transporting beams of different wavelengths with different intensities and shapes can be modulated by adjusting the wavelength and intensity of the controlling beam.

  7. Tunable Microwave Photonic Notch Filter Based on a high-birefringence linearly chirped fiber Bragg grating

    International Nuclear Information System (INIS)

    In this paper, a continuously tunable microwave photonic notch filter is proposed and experimentally demonstrated. This filter is based on the differential group delay generated by a high-birefringence linearly chirped fiber Bragg grating. This microwave photonic filter belongs to the orthogonal polarization approach, polarization maintaining structure ensures the filter free from the random optical interference problem. Its response is induced by the differential group delay (DGD) of the Hi-Bi LCFBG and it can be varied by tuning the grating through adding gradient strength to the grating. Free spectral range tuning by 9.27 GHz with more than 35 dB notch rejection is achieved.

  8. Crystalline perfection, birefringence and laser damage threshold properties of piperidinium p-hydroxybenzoate

    International Nuclear Information System (INIS)

    Piperidinium p-hydroxybenzoate (PPHB) crystal was grown by slow evaporation method. Single crystal X-ray diffraction studies confirm that PPHB crystallizes in monoclinic crystal system with noncentrosymmetric space group Cc. The crystalline perfection of the grown crystal was evaluated by using high resolution X-ray diffractometry. UV-Visible transmission and birefringence studies were employed on the grown PPHB crystal. The laser induced damage threshold value was estimated using Nd:YAG laser. Thermal behavior of PPHB crystal has been investigated by TG-DTA analyses. Etching studies have been performed to assess the growth pattern of PPHB crystal

  9. Cross-phase modulational instability induced by Raman scattering in highly birefringent fiber.

    Science.gov (United States)

    Amrani, Foued; Kibler, Bertrand; Grelu, Philippe; Wabnitz, Stefan; Trillo, Stefano; Millot, Guy

    2013-12-15

    We report experimental and theoretical studies of Raman-induced cross-phase modulational instabilities (XPMI) in a high-birefringence, normally dispersive optical fiber. Experimental results reveal that the Raman-Stokes wave, generated by a quasi-CW pump beam, interacts with the latter to create a novel type of XPMI sidebands. These sidebands are characterized by a narrow gain bandwidth. The sideband frequencies are well reproduced by a linear stability analysis as well as by full numerical solutions of the coupled generalized nonlinear Schrödinger equations. PMID:24322249

  10. The temperature dependence of the optical anisotropy in magnetic fluids: birefringence and dichroism

    Science.gov (United States)

    Yusuf, N. A.; Manasrah, D. A.; Abdallah, M. A.; Abu-Safia, H.; Abu-Aljarayesh, I.

    1994-11-01

    The temperature dependence of birefringence, δ, and dichroism, Δ A, in Fe 3O 4 Isopar-M based magnetic fluids have been investigated in the temperature range 100 Tm. The values of Tm and Ts are found to vary with concentration and the applied field. The results also show that δ- H2 and Δ A-H2 curves deviate from linearity. This deviation is attributed to interparticle interactions, the orientation of pre-existing clusters, and the field-induced chain formation.

  11. Digital polarization holograms with defined magnitude and orientation of each pixel's birefringence.

    Science.gov (United States)

    Fratz, Markus; Giel, Dominik M; Fischer, Peer

    2009-04-15

    A new form of digital polarization holography is demonstrated that permits both the amplitude and the phase of a diffracted beam to be independently controlled. This permits two independent intensity images to be stored in the same hologram. To fabricate the holograms, a birefringence with defined retardance and orientation of the fast axis is recorded into a photopolymer film. The holograms are selectively read out by choosing the polarization state of the read beam. Polarization holograms of this kind increase the data density in holographic data storage and allow higher quality diffractive optical elements to be written. PMID:19370140

  12. The measurement of temperature with using of birefringence crystals as detectors

    OpenAIRE

    Gaba V.M.

    2009-01-01

    The carried out researches allowed to motivate and put into practice the polarizatoin-optical method of temperature measurement based on the phenomenon of temperature alteration in value of birefringence of the optically anisotropic crystals. The practical realization of the method with the use of Al2O3 and LiNbO3 plates as active elements of thermometers has shown, that the application of Al2O3 is more preferable due to a wide temperature interval of employment of material, its mechanical an...

  13. External-cavity birefringence feedback effects of microchip Nd:YAG laser and its application in angle measurement

    Institute of Scientific and Technical Information of China (English)

    Ren Cheng; Tan Yi-Dong; Zhang Shu-Lian

    2009-01-01

    External-cavity birefringence feedback effects of the microchip Nd:YAG laser are presented.When a birefringence element is placed in the external feedback cavity of the laser,two orthogonally polarized laser beams with a phase difference are output.The phase difference is twice as large as the phase retardation in the external cavity along the two orthogonal directions.The variable extra-cavity birefringence,caused by rotation of the external-cavity birefringenee element,results in tunable phase difference between the two orthogonally polarized beams.This means that the roll angle information has been translated to phase difference of two output laser beams.A theoretical analysis based on the Fabry-Perot cavity equivalent model and refractive index ellipsoid is presented,which is in good agreement with the experimental results.This phenomenon has potential applications for roll angle measurement.

  14. Further comments on the effects of vacuum birefringence on the polarization of X-rays emitted from magnetic neutron stars

    Science.gov (United States)

    Chanan, G. A.; Novick, R.; Silver, E. H.

    1979-01-01

    The birefringence of the vacuum in the presence of strong (of the order of 1 teragauss) magnetic fields will in general affect the polarization of X-rays propagating through these fields. Two of the four Stokes parameters will vary so rapidly with wavelength as to be 'washed out' and unobservable, but the remaining two parameters will be unaffected. These results show that one conclusion of an earlier work is incorrect: Polarized X-ray emission from the surface of a magnetic neutron star will not in general be completely depolarized by the effects of vacuum birefringence. In particular, this birefringence has no effect on the linear polarization of cyclotron emission from the poles of magnetic neutron stars, and a similar result holds for synchrotron emission. More general cases of the propagation of polarized X-rays in magnetic fields are also discussed.

  15. Nonlinear polarization dynamics in a weakly birefringent all-normal dispersion photonic crystal fiber : toward a practical coherent fiber supercontinuum laser

    DEFF Research Database (Denmark)

    Tu, Haohua; Liu, Yuan; Liu, Xiaomin;

    2012-01-01

    be qualitatively or semi-quantitatively understood by the coupled GNLSE that takes into account the form-birefringence. The nonlinear polarization effects induced by the birefringence significantly distort the otherwise simple spectrotemporal field of the SC pulses. We therefore propose the...... fabrication of polarization-maintaining DFDD-ANDi fibers to avoid these adverse effects in pursuing a practical coherent fiber SC laser....

  16. Temperature Compensated Strain Sensor Based on Cascaded Sagnac Interferometers and All-Solid Birefringent Hybrid Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Wu; He, Sailing;

    2012-01-01

    We demonstrate a temperature compensated strain sensor with two cascaded Sagnac interferometers, that provide strain sensing and temperature compensation, respectively. The Sagnac interferometers use an all-solid hybrid photonic crystal fiber with stress-induced birefringence. The stress......-induced birefringent fiber is known to offer the maximum strain sensitivity, but also to suffer from temperature crosstalk. Our experimental results show that the cascaded Sagnac sensor can suppress the crosstalk to a temperature upto 0.33 με/ºC, while still providing a high strain sensitivity of ~25.6 pm}/με....

  17. The system spatial-frequency filtering of birefringence images of human blood layers

    Science.gov (United States)

    Ushenko, A. G.; Boychuk, T. M.; Mincer, O. P.; Angelsky, P. O.; Bodnar, N. B.; Oleinichenko, B. P.; Bizer, L. I.

    2013-09-01

    Among various opticophysical methods [1 - 3] of diagnosing the structure and properties of the optical anisotropic component of various biological objects a specific trend has been singled out - multidimensional laser polarimetry of microscopic images of the biological tissues with the following statistic, correlative and fractal analysis of the coordinate distributions of the azimuths and ellipticity of polarization in approximating of linear birefringence polycrystalline protein networks [4 - 10]. At the same time, in most cases, experimental obtaining of tissue sample is a traumatic biopsy operation. In addition, the mechanisms of transformation of the state of polarization of laser radiation by means of the opticoanisotropic biological structures are more varied (optical dichroism, circular birefringence). Hereat, real polycrystalline networks can be formed by different types, both in size and optical properties of biological crystals. Finally, much more accessible for an experimental investigation are biological fluids such as blood, bile, urine, and others. Thus, further progress of laser polarimetry can be associated with the development of new methods of analysis and processing (selection) of polarization- heterogeneous images of biological tissues and fluids, taking into account a wider set of mechanisms anisotropic mechanisms. Our research is aimed at developing experimental method of the Fourier polarimetry and a spatialfrequency selection for distributions of the azimuth and the ellipticity polarization of blood plasma laser images with a view of diagnosing prostate cancer.

  18. Linear birefringence and dichroism measurement in oil-based Fe3O4 magnetic nanoparticles

    Science.gov (United States)

    Lin, Jing-Fung; Wang, Chia-Hung; Lee, Meng-Zhe

    2013-04-01

    To prepare dispersed Fe3O4 magnetic nanoparticles (MNPs), we adopt a co-precipitation method and consider surfactant amount, stirring speed, dispersion mode, and molar ratio of Fe3+/Fe2+. Via transmission electronic microscopy and X-ray diffractometry, we characterize the dispersibility and size of the products and determine the appropriate values of experimental parameters. The stirring speed is 1000 rpm in titration. There is simultaneous ultrasonic vibration and mechanical stirring in the titration and surface coating processes. The surfactant amount of oleic acid is 1.2 ml for molar ratios of Fe3+/Fe2+ as 1.7:1, 1.8:1, and 1.9:1. The average diameters of these Fe3O4 MNPs are 11 nm, and the ratios of saturation magnetization for these MNPs to that of bulk magnetite range from 45% to 65%, with remanent magnetization close to zero and low coercivity. Above all, the linear birefringence and dichroism measurements of the kerosene-based ferrofluid (FF) samples are investigated by a Stokes polarimeter. The influences of particle size distribution and magnetization in the birefringence and dichroism measurements of FFs are discussed.

  19. High Magnetic Field-Induced Birefringence in Lyotropic Chromonic Liquid Crystals

    Science.gov (United States)

    Ostapenko, T.; Nastishin, Yu.; Gleeson, J. T.; Sprunt, S. N.; Lavrentovich, O. D.; Collings, P. J.

    2009-03-01

    We studied the effect of magnetic-field induced birefringence of a 14% solution of disodium cromoglycate (DSCG) in water at temperatures above the nematic-isotropic coexistence region. According to Landau-deGennes mean field theory, we expect to find a linear relationship between the inverse of the induced birefringence, δn, and the quantity (T-T*), where T* is the stability limit of the isotropic phase. Using the 31 T resistive magnet at the National High Magnetic Field Laboratory, we observed that, as we increase the temperature above the coexistence region, we deviate from this linear dependence. Our data shows that δn goes to zero, whereas Landau-deGennes predicts that δn should decrease asymptotically. This may be due to the lack of isodesmic aggregate formation at a finite temperature above the coexistence region.Supported by NSF (DMR-0710544 and DMR-0606160). Work performed at NHMFL, supported by NSF cooperative agreements DMR-0084173, the State of Florida and the DOE.

  20. Compact snapshot birefringent imaging Fourier transform spectrometer for remote sensing and endoscopy

    Science.gov (United States)

    Kudenov, Michael W.; Banerjee, Bhaskar; Chan, Victoria C.; Dereniak, Eustace L.

    2012-09-01

    The design and implementation of a compact multiple-image Fourier transform spectrometer (FTS) is presented. Based on the multiple-image FTS originally developed by A. Hirai, the presented device offers significant advantages over his original implementation. Namely, its birefringent nature results in a common-path interferometer which makes the spectrometer insensitive to vibration. Furthermore, it enables the potential of making the instrument ultra-compact, thereby improving the portability of the sensor. The theory of the birefringent FTS is provided, followed by details of its specific embodiment. A laboratory proof of concept of the sensor, designed and developed at the Optical Detection Lab, is also presented. Spectral measurements of laboratory sources are provided, including measurements of light-emitting diodes and gas-discharge lamps. These spectra are verified against a calibrated Ocean Optics USB2000 spectrometer. Other data were collected outdoors and of a rat esophagus, demonstrating the sensor's ability to resolve spectral signatures in both standard outdoor lighting and environmental conditions, as well as in fluorescence spectroscopy.

  1. Effects of Ellipticity Angle on Modulation Instabilities in Birefringent Optical Fibers

    Science.gov (United States)

    Li, Jin-Hua; Chow, K. W.; Liu, Ping; Hu, Yong-Zheng; Sun, Ting-Ting

    2016-02-01

    Previous studies on modulation instabilities (MIs) in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fibers with the emphasis on investigating the effects of ellipticity angle (0° ≤ θ ≤ 90°). Both symmetric and antisymmetric CW states are considered. In the anomalous dispersion regime, for the symmetric (antisymmetric) CW states, we show that MI gain increases dramatically (reduces first and then enhances greatly) as the increment of θ. In the normal dispersion regime, for the both CW states, the distinctive feature is that the gain of the MI bands reduces first, vanishes at θ = 45°, reappears across this ellipticity angle, and quickly increases after then. Supported by the National Natural Science Foundation of China under Grant Nos. 11447113 and 11305031, Natural Science Foundation of Jiangsu Provincial Universities under Grant No. 14KJB140009, and the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology under Grant No. 2241131301064

  2. Optical activity of a single MnAs cluster: Birefringence or Kerr effect

    Science.gov (United States)

    Leuschner, M.; Klar, P. J.; Heimbrodt, W.; Rühle, W. W.; Hara, S.; Stolz, W.; Volz, K.; Kurz, T.; Loidl, A.; Krug von Nidda, H.-A.

    2006-06-01

    We have grown In 0.54Ga 0.46As:Mn/MnAs granular paramagnetic-ferromagnetic hybrid structures by metal-organic vapor-phase epitaxy. The MnAs clusters have a Curie temperature of about 320 K. We have studied the optical activity of individual ferromagnetic MnAs clusters embedded in the paramagnetic In 0.54Ga 0.46As:Mn matrix at room temperature by far-field depolarization measurements. A scanning near-field optical microscopy set-up in constant height mode ( ≈100 nm above the sample surface) was used to achieve a high spatial resolution. Individual MnAs clusters rotate the linear polarization of the incoming light by almost 2∘ in this reflection geometry. This optical activity was analyzed in terms of birefringence and polar Kerr effect and correlated with the structural and magnetic properties of the MnAs clusters as determined by ferromagnetic resonance measurements. The optical activity of the MnAs clusters turns out to be dominated by linear birefringence caused by the uniaxial symmetry of the hexagonal crystal structure of MnAs. The polar Kerr effect plays a minor role in this experiment.

  3. Optical activity of a single MnAs cluster: Birefringence or Kerr effect

    Energy Technology Data Exchange (ETDEWEB)

    Leuschner, M. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Klar, P.J. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany)]. E-mail: peter.klar@physik.uni-marburg.de; Heimbrodt, W. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Ruehle, W.W. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Hara, S. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-0197 (Japan); Stolz, W. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Volz, K. [Department of Physics and Material Sciences Center, Philipps University, Renthof 5, 35032 Marburg (Germany); Kurz, T. [Experimentalphysik V, Elektronische Korrelationen und Magnetismus, Institut fuer Physik, Universitaet Augsburg, 86135 Augsburg (Germany); Loidl, A. [Experimentalphysik V, Elektronische Korrelationen und Magnetismus, Institut fuer Physik, Universitaet Augsburg, 86135 Augsburg (Germany); Krug von Nidda, H.-A. [Experimentalphysik V, Elektronische Korrelationen und Magnetismus, Institut fuer Physik, Universitaet Augsburg, 86135 Augsburg (Germany)

    2006-06-15

    We have grown In{sub 0.54}Ga{sub 0.46}As:Mn/MnAs granular paramagnetic-ferromagnetic hybrid structures by metal-organic vapor-phase epitaxy. The MnAs clusters have a Curie temperature of about 320K. We have studied the optical activity of individual ferromagnetic MnAs clusters embedded in the paramagnetic In{sub 0.54}Ga{sub 0.46}As:Mn matrix at room temperature by far-field depolarization measurements. A scanning near-field optical microscopy set-up in constant height mode ({approx}100nm above the sample surface) was used to achieve a high spatial resolution. Individual MnAs clusters rotate the linear polarization of the incoming light by almost 2{sup -}bar in this reflection geometry. This optical activity was analyzed in terms of birefringence and polar Kerr effect and correlated with the structural and magnetic properties of the MnAs clusters as determined by ferromagnetic resonance measurements. The optical activity of the MnAs clusters turns out to be dominated by linear birefringence caused by the uniaxial symmetry of the hexagonal crystal structure of MnAs. The polar Kerr effect plays a minor role in this experiment.

  4. Constraints on cosmological birefringence from Planck and Bicep2/Keck data

    CERN Document Server

    Gruppuso, A; Natoli, P; Pagano, L; Mandolesi, N; Molinari, D

    2015-01-01

    The polarization of cosmic microwave background (CMB) can be used to constrain cosmological birefringence, the rotation of the linear polarization of CMB photons potentially induced by parity violating physics beyond the standard model. This effect produces non-null CMB cross correlations between temperature and B mode-polarization, and between E- and B-mode polarization. Both cross-correlations are otherwise null in the standard cosmological model. We use the recently released 2015 Planck likelihood in combination with the Bicep2/Keck/Planck (BKP) likelihood to constrain the birefringence angle $\\alpha$. Our findings, that are compatible with no detection, read $\\alpha = 0.0^{\\circ} \\pm 1.3^{\\circ} \\mbox{ (stat)} \\pm 1^{\\circ} \\mbox{ (sys)} $ for {\\sc Planck} data and $\\alpha = 0.30^{\\circ} \\pm 0.27^{\\circ} \\mbox{ (stat)} \\pm 1^{\\circ} \\mbox{(sys)} $ for BKP data. We finally forecast the expected improvements over present constraints when the Planck BB, TB and EB spectra at high $\\ell$ will be included in th...

  5. Constraints on cosmological birefringence from PLANCK and Bicep2/Keck data

    Science.gov (United States)

    Gruppuso, A.; Gerbino, M.; Natoli, P.; Pagano, L.; Mandolesi, N.; Melchiorri, A.; Molinari, D.

    2016-06-01

    The polarization of cosmic microwave background (CMB) can be used to constrain cosmological birefringence, the rotation of the linear polarization of CMB photons potentially induced by parity violating physics beyond the standard model. This effect produces non-null CMB cross correlations between temperature and B mode-polarization, and between E- and B-mode polarization. Both cross-correlations are otherwise null in the standard cosmological model. We use the recently released 2015 PLANCK likelihood in combination with the Bicep2/Keck/Planck (BKP) likelihood to constrain the birefringence angle α. Our findings, that are compatible with no detection, read α = 0.0° ± 1.3° (stat) ± 1° (sys) for PLANCK data and α = 0.30° ± 0.27° (stat) ± 1° (sys) for BKP data. We finally forecast the expected improvements over present constraints when the PLANCK BB, TB and EB spectra at high l will be included in the analysis.

  6. Annealing of linear birefringence in single-mode fiber coils - Application to optical fiber current sensors

    Science.gov (United States)

    Tang, Dingding; Rose, A. H.; Day, G. W.; Etzel, Shelley M.

    1991-01-01

    Annealing procedures that greatly reduce linear birefringence in single-mode fiber coils are described. These procedures have been successfully applied to coils ranging from 5 mm to 10 cm in diameter and up to 200 or more turns. They involve temperature cycles that last 3-4 days and reach maximum temperatures of about 850 C. The residual birefringence and induced loss are minimized by proper selection of fiber. The primary application of these coils is optical fiber current sensors, where they yield small sensors that are more stable than those achieved by other techniques. A current sensor with a temperature stability of 8.4 x 10 to the -5th/K over the range from -75 to 145 C has been demonstrated. This is approximately 20 percent greater than the temperature dependence of the Verdet constant. Packaging degrades the stability, but a packaged sensor coil with a temperature stability of about 1.6 + 10 to the -4th/K over the range from -20 to 120 C has also been demonstrated.

  7. Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ganapati, Vidya; Schoenfelder, Stephan; Castellanos, Sergio; Oener, Sebastian; Koepge, Ringo; Sampson, Aaron; Marcus, Matthew A.; Lai, Barry; Morhenn, Humphrey; Hahn, Giso; Bagdahn, Joerg; Buonassisi1, Tonio

    2010-05-05

    This manuscript concerns the application of infrared birefringence imaging (IBI) to quantify macroscopic and microscopic internal stresses in multicrystalline silicon (mc-Si) solar cell materials. We review progress to date, and advance four closely related topics. (1) We present a method to decouple macroscopic thermally-induced residual stresses and microscopic bulk defect related stresses. In contrast to previous reports, thermally-induced residual stresses in wafer-sized samples are generally found to be less than 5 MPa, while defect-related stresses can be several times larger. (2) We describe the unique IR birefringence signatures, including stress magnitudes and directions, of common microdefects in mc-Si solar cell materials including: {beta}-SiC and {beta}-Si{sub 3}N{sub 4} microdefects, twin bands, nontwin grain boundaries, and dislocation bands. In certain defects, local stresses up to 40 MPa can be present. (3) We relate observed stresses to other topics of interest in solar cell manufacturing, including transition metal precipitation, wafer mechanical strength, and minority carrier lifetime. (4) We discuss the potential of IBI as a quality-control technique in industrial solar cell manufacturing.

  8. Macroscopic birefringence in liquid crystals from novel cyanobacterial polysaccharide with an extremely high molecular weight

    Science.gov (United States)

    Okajima-Kaneko, Maiko; Hayasaka-Kaneko, Daisaku; Miyazato, Shinji; Kaneko, Tatsuo

    2007-05-01

    We report an efficient method for extraction of anionic polysaccharides (PS) from cyanobacteria, Aphanothece sacrum; we used a hot alkaline solution (0.01 N NaOH) as an elution solvent in the first step of the extraction and isopropanol as a precipitation solvent in the last step. Thin fibers of PS were obtained at a high yield (50-80 % to the weight of the raw cyanobacterial sample). The spectroscopy and elemental analyses indicated the PS contains fucose, uronic acids (14.2 % by a carbazole-sulfuric acid method), a sugar unit containing amides. The solution of PS with a concentration of 1 wt% showed a very high viscosity (80 000cps) implying a high molecular weight, and a strong macroscopic birefringence with a texture typical of nematic liquid crystals was confirmed by crossed-polarizing microscopy (more than 0.5 wt%). The PS from A. sacrum may form a special structure rigid-rod enough to show LC phase and macroscopic birefringence.

  9. Periodic reversal of magneto-optic Faraday rotation on uniaxial birefringence crystal with ultrathin magnetic films

    Directory of Open Access Journals (Sweden)

    C. W. Su

    2013-07-01

    Full Text Available An experimental approach of inclined incidence magneto-optic Faraday effect observed in the polar plane is applied. Three samples containing ferromagnetic cobalt ultrathin films on a semiconductor zinc oxide (0001 single crystal substrate with in-plane and out-of-plane anisotropy are evaluated. Through the fine adjustment of crossed polarizers in the magneto-optic effect measurement completely recorded the detail optical and magneto-optical responses from the birefringent crystal substrate and the magnetic film, especially for the signal induced from the substrate with uniaxial optical axis. The angle dependency of interference phenomena periodically from the optical and magneto-optical responses is attributed to the birefringence even in the absence of a magnetic field. The new type of observation finds that the transmission Faraday intensity in the oblique incidence includes a combination of polarization rotations, which results from optical compensation from the substrate and magneto-optical Faraday effects from the film. The samples grown at different rates and examined by this method exhibit magnetic structure discriminations. This result can be applied in the advanced polarized-light technologies to enhance the spatial resolution of magnetic surfaces with microstructural information under various magnetic field direction.

  10. Birefringence gradient development during drying of solution cast functional films and their mechanical, optical and gas barrier properties

    Science.gov (United States)

    Yucel, Orcun

    For the first time, the development of optical anisotropy gradient as a result of solvent evaporation for poly (amide-imide) (PAI) solution in Dimethylacetamide (DMAc) was investigated. Experiments were carried out using real time optical measurement with spectral birefringence technique coupled with off-line optical techniques such as Abbe refractometer and optical compensator method. Drying process induced temporal evolution of non-uniform out of plane birefringence profile through the thickness direction while in plane birefringence remained zero. The highest birefringence was observed at the substrate-solution interface at early stages of drying. Beyond a critical time, the formation of highly oriented layer was observed at the air-solution interface. This oriented layer progresses through the thickness direction as the solvent concentration is disproportionately reduced in these regions. Abbe refractometer results confirmed the anisotropy is preserved at longer drying times, air-solution interface birefringence becoming higher compared to substrate-solution interface. Overall, observations obtained by real-time measurement system agreed with off-line measurements. In additon, multifunctional single and triple-layer films exhibiting flexibility, high modulus and high gas barrier properties were developed using a soluble polyamide-imide (PAI) in dimethylacetamide (DMAc) with ammonium-modified montmorillonite (MMT, Cloisite 30B) mineral clay. The drying behavior and associated anisotropy development were determined real-time, using a newly developed real-time measurement system. Increase in organoclay content resulted in higher viscosity values. This behavior was reversed at high shear rates. Out-of-plane birefringence development occurred earlier for thinner neat samples caused by increased depletion rate of solvent. Addition of organoclay content resulted in a decrease in evaporation rate of solvent due to planar orientation of well exfoliated nanoplatelets as

  11. Deep tissue volume imaging of birefringence through fibre-optic needle probes for the delineation of breast tumour

    Science.gov (United States)

    Villiger, Martin; Lorenser, Dirk; McLaughlin, Robert A.; Quirk, Bryden C.; Kirk, Rodney W.; Bouma, Brett E.; Sampson, David D.

    2016-07-01

    Identifying tumour margins during breast-conserving surgeries is a persistent challenge. We have previously developed miniature needle probes that could enable intraoperative volume imaging with optical coherence tomography. In many situations, however, scattering contrast alone is insufficient to clearly identify and delineate malignant regions. Additional polarization-sensitive measurements provide the means to assess birefringence, which is elevated in oriented collagen fibres and may offer an intrinsic biomarker to differentiate tumour from benign tissue. Here, we performed polarization-sensitive optical coherence tomography through miniature imaging needles and developed an algorithm to efficiently reconstruct images of the depth-resolved tissue birefringence free of artefacts. First ex vivo imaging of breast tumour samples revealed excellent contrast between lowly birefringent malignant regions, and stromal tissue, which is rich in oriented collagen and exhibits higher birefringence, as confirmed with co-located histology. The ability to clearly differentiate between tumour and uninvolved stroma based on intrinsic contrast could prove decisive for the intraoperative assessment of tumour margins.

  12. Group velocity dispersion and polarization mode dispersion compensation by high-birefringence linearly chirped fiber Bragg grating

    Institute of Scientific and Technical Information of China (English)

    Muguang Wang(王目光); Tangjun Li(李唐军); Shuisheng Jian(简水生)

    2004-01-01

    A high-birefringence linearly chirped fiber Bragg grating (FBG) is written into a polarization-maintaining photosensitive fiber by ultraviolet (UV) beam through a linearly chirped phase mask. Its performance as group velocity dispersion (GVD) and polarization mode dispersion (PMD) compensator is demonstrated in short pulse fiber optical transmission systems.

  13. All-solid birefringent hybrid photonic crystal fiber based interferometric sensor for measurement of strain and temperature

    DEFF Research Database (Denmark)

    Gu, Bobo; Yuan, Scott Wu; Zhang, A. Ping;

    2011-01-01

    A highly sensitive fiber-optic interferometric sensor based on an all-solid birefringent hybrid photonic crystal fiber (PCF) is demonstrated for measuring strain and temperature. A strain sensitivity of similar to 23.8 pm/mu epsilon and a thermal sensitivity of similar to-1.12 nm/degrees C are...

  14. Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles

    Directory of Open Access Journals (Sweden)

    Silva Liliane FI

    2011-04-01

    Full Text Available Abstract Background This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF intensity and the nuclear (NM and cytoplasmic (CM in vitro maturation of human oocytes from stimulated cycles. Results The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence or low/negative (when the image presented moderate and heterogeneous birefringence. CM was analyzed by evaluating the distribution of cortical granules (CGs throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV stage oocytes, 58 of oocytes (69.9% reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55. These variables had a low Pearson's correlation coefficient (r = 0.081. Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6% showed the complete CM, 30 (61.2% presented a high/positively scoring ZP-BF and 19 (38.8% had a low/negatively scoring ZP-BF. From 36 oocytes (42.3% with incomplete CM, 18 (50% presented a high/positively scoring ZPBF and 18 (50% had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42. These variables had a low Pearson's correlation coefficient (r = 0.11. Conclusions The current

  15. Dynamics of creation photoinduced birefringence on (PAH/PAZO)n layer-by-layer films: Analysis of consecutive cycles

    Science.gov (United States)

    Timóteo, Ana Rita Monteiro; Ribeiro, Jorge H. F.; Ribeiro, Paulo A.; Raposo, Maria

    2016-01-01

    Reproducibility and reliability of data is an important subject in the development of organic devices for photonics applications. This work reports the analysis of successive photoinduced birefringence creation curves in layer-by-layer films of poly(allylamine hydrochloride) (PAH) and poly{1-(4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido)-1,2-ethanediyl, sodium salt} (PAZO) with different number of bilayers. The birefringence creation or writing curves are described by two processes: a faster one referring the contribution of trans-cis-trans photoisomerization cycles to the birefringence; and a slower one associated to the contribution of motion of the polymer chain to the birefringence. As the number of write-erase cycles increases, the characteristic times of these processes decreases, respectively, to values of 18 and 212 s independently of the number of bilayers of films while for the magnitudes the fast process prevailed relatively to the slow, by 70% against 30%. The observed behavior is explained by the thermal treatment given by the laser beam in the irradiated area with increase of free volume which contributes for the chromophore mobility. This conclusion was achieved by measuring the surface temperature during and after irradiation and analyzing by optical microscopy the film surface where an increase of holes and aggregation as a result of irradiation was observed. Infrared spectra of films after and before irradiation showed changes in the Cdbnd C absorbance indicating aggregation of azobenzene groups while changes in the protonated and deprotonated carboxylic acid groups are consistent with ionization degree diminishing which is explained by the removal of water molecules by heating caused by laser. The results presented in this paper indicates that an increase in the number of write-erase cycles contributes to reliable and reproducible birefringence characteristics of PAH/PAZO films - a good new from point of view of possible applications.

  16. Localization length calculations in alternating metamaterial-birefringent disordered layered stacks

    CERN Document Server

    del Barco, O; Gevorkian, Zh

    2015-01-01

    A detailed theoretical and numerical analysis of the localization length in alternating metamaterial-birefringent random layered stacks, under uncorrelated thickness-disorder, has been performed. Similar structures have recently been reported to suppress the Brewster delocalization for $\\it{p}$-polarized light, when "standard" isotropic layers (with positive index of refraction) are considered instead of metamaterial layers, providing a generic means to produce polarization-insensitive, broadband reflections. However, this enhancement of localization is valid for short wavelengths $\\lambda$ compared to the mean layer thickness $a_0$. At higher wavelengths, we recover the Brewster anomalies for $\\it{p}$-polarized states impeding a remarkable localization of light. To achieve a better localization for a wider range of wavelengths, we replaced the conventional isotropic layers by negative-index metamaterials presenting low losses and constant index of refraction over the near-infrared range. As a result, our num...

  17. Theoretical simulation of a novel birefringent photonic crystal fiber with surface plasmon resonance around 1300 nm

    Science.gov (United States)

    Duanming, Li; Guiyao, Zhou

    2016-03-01

    In this paper, a novel birefringent photonic crystal fiber (PCF) with the silver-coated and liquid-filled air-holes along the vertical plane is designed. Simulation results show that the thickness of silver layer, the sizes of holes, and the refractive index of liquid strongly strengthen the gaps between two polarized directions. The surface plasmon resonance peak along y axis can be up to 675.8 dB/cm at 1.33 μm. The proposed PCF has important application in polarization devices, such as filters and beam splitters. Project partly supported by the National Basic Research Development Program of China (Grant No. 2010CB327604), the National Natural Science Foundation of China (Grant No. 61377100), and the Natural Science Foundation of Guangdong Province, China (Grant No. S2013040015665).

  18. The measurement of temperature with using of birefringence crystals as detectors

    Directory of Open Access Journals (Sweden)

    Gaba V. M.

    2009-02-01

    Full Text Available The carried out researches allowed to motivate and put into practice the polarizatoin-optical method of temperature measurement based on the phenomenon of temperature alteration in value of birefringence of the optically anisotropic crystals. The practical realization of the method with the use of Al2O3 and LiNbO3 plates as active elements of thermometers has shown, that the application of Al2O3 is more preferable due to a wide temperature interval of employment of material, its mechanical and chemical stability, absence of phase transitions. LiNbO3 has such lacks as nonlinearity of graduate dependence and presence of a phase transition point. Nevertheless, its use allows to raise the sensitivity of the thermometer and to increase the accuracy of measurements.

  19. Circular and linear magnetic birefringences in xenon at $\\lambda = 1064$ nm

    CERN Document Server

    Cadène, Agathe; Rivère, Alice; Battesti, Remy; Coriani, Sonia; Rizzo, Antonio; Rizzo, Carlo

    2015-01-01

    The circular and linear magnetic birefringences corresponding to the Faraday and the Cotton-Mouton effects, respectively, have been measured in xenon at $\\lambda = 1064$ nm. The experimental setup is based on time dependent magnetic fields and a high finesse Fabry-Perot cavity. Our value of the Faraday effect is the first measurement at this wavelength. It is compared to theoretical predictions. Our uncertainty of a few percent yields an agreement at better than 1$\\sigma$ with the computational estimate when relativistic effects are taken into account. Concerning the Cotton-Mouton effect, our measurement, the second ever published at $\\lambda = 1064$ nm, agrees at better than $1\\sigma$ with theoretical predictions. We also compare our error budget with those established for other experimental published values.

  20. Semiconductor optical amplifier direct modulation with double-stage birefringent fiber loop

    Science.gov (United States)

    Engel, Thomas; Rizou, Zoe V.; Zoiros, Kyriakos E.; Morel, Pascal

    2016-06-01

    The feasibility of cascading two birefringent fiber loops (BFLs) for directly modulating a conventional semiconductor optical amplifier (SOA) at a faster data rate than that being possible by its limited electrical bandwidth is demonstrated for the first time. The experimental results reveal the improvements in the quality characteristics of the encoded signal compared to those achieved with a single-stage BFL. The observed trends are complemented by numerical simulations, which allow to investigate the impact of the double-stage BFL detuning and specify how this critical parameter must be selected for enhanced performance. Provided that it is properly tailored, the proposed optical notch filtering scheme efficiently compensates for the pattern-dependent SOA response and enables this element to be employed as intensity modulator with improved performance at enhanced data speeds.

  1. Feasibility Study of an Experiment to Measure the Vacuum Magnetic Birefringence

    CERN Document Server

    Pugnat, P; Finger, Miroslav H; Kral, M; Siemko, A; Zicha, J

    2005-01-01

    The use of a recently decommissioned 15-meters long twin aperture LHC superconducting magnet prototype having a transverse magnetic field B ~ 9.5 T provides the unique opportunity for the construction of a new powerful experiment to measure the Vacuum Magnetic Birefringence (VMB). The values or the limit values of the mass and of the coupling constant to two photons of possible dark matter candidates such as axions are aimed to be deduced from such an experiment. In this article, the technical feasibility study of a new setup to measure the VMB will be presented. It is based on a linear optical resonant cavity housed in the LHC superconducting dipole prototype. The mechanical integrations of the optical components inside the magnet aperture as well as the optical detection principles will be presented. A comparison of the expected performances with respect to the present reference results for this type of experiment will also be given.

  2. Feasibility study of an experiment to measure the vacuum magnetic birefringence

    International Nuclear Information System (INIS)

    The use of a recently decommissioned 15-meters long twin aperture LHC superconducting magnet prototype having a transverse magnetic field B ≅ 9.5 T provides the unique opportunity for the construction of a new powerful experiment to measure the Vacuum Magnetic Birefringence (VMB). The values or the limit values of the mass and of the coupling constant to two photons of possible dark matter candidates such as axions are aimed to be deduced from such an experiment. In this article, the technical feasibility study of a new setup to measure the VMB will be presented. It is based on a linear optical resonant cavity housed in the LHC superconducting dipole prototype. The mechanical integrations of the optical components inside the magnet aperture as well as the optical detection principles will be presented. A comparison of the expected performances with respect to the present reference results for this type of experiment will also be given. (author)

  3. Polarized light imaging of birefringence and diattenuation at highresolution and high sensitivity

    CERN Document Server

    Mehta, Shalin B; 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 either instrument, and touch on the physical connection between ...

  4. In vitro birefringence imaging with spectral domain polarization-sensitive optical coherence tomography

    Institute of Scientific and Technical Information of China (English)

    Qiang Gong; Chuanmao Fan; Fan Zhang; Jianquan Yao

    2008-01-01

    Spectral domain polarization-sensitive optical coherence tomography (SDPS-OCT) is a depth-resolved polarization-sensitive interferometry which integrates polarization optics into spectral domain optical co-herence tomography (SD-OCT). This configuration can obtain birefringence information of samples and improve the imaging speed. In this paper, horizontally polarized light is used to replace natural light of the source. Then, right-rotated circularly polarized light is the incident sample light. To obtain two orthogonal components of the polarized interferogram, the reflected light of the reference arm is set to be 45° linearly polarized light. These two components are acquired by two spectrometers synchronously. The system was employed to achieve 12.8-#m axial resolution and 4.36-#m transverse resolution. We have imaged in vitro chicken tendon and muscle tissues with these system.

  5. Distributed measurement of mode coupling in birefringent fibers with random polarization modes

    CERN Document Server

    Xu, Tianhua; Jing, Wencai; Zhang, Hongxia; Jia, Dagong; Zhang, Xuemin; Zhou, Ge; Zhang, Yimo

    2016-01-01

    A scanning white light interferometer is developed to measure the distributed polarization coupling (DPC) in high birefringence polarization maintaining fibers (PMFs). Traditionally, this technique requests only one polarization mode to be excited or both polarization modes to be excited with equal intensity in the PMF. Thus, an accurate alignment of the polarization direction with the principal axis in PMF is strictly required, which is not facilely realized in practical measurement. This paper develops a method to measure the spatial distribution of polarization mode coupling with random modes excited using a white light Michelson interferometer. The influence of incident polarization extinction ratio (PER) on polarization coupling detection is evaluated theoretically and experimentally. It is also analyzed and validated in corresponding measurement that the sensitivity of the polarization coupling detection system can be improved more than 100 times with the rotation of the analyzer.

  6. Diode-pumped Birefringent Tunable Nd: YAG Laser with Large Frequency Difference

    Institute of Scientific and Technical Information of China (English)

    CHANG Li; ZHANG Shulian; HAN Yanmei; LI Yan

    2001-01-01

    A dual-frequency Nd: YAG laser which can output two frequencies with frequency difference of more than 5 gigaherz is developed. By inserting and moving an intracavity quartz crystal wedge in diode pumped Nd:YAG laser, It can be obtained and tuned frequency difference in a wide frequency range. The stabilization of frequency difference in free state is much better than that of birefringent dual-frequency He-Ne lasers at similar laboratory conditions. With such a large tunable frequency difference i.e. short synthetic wavelength, the laser may be used as the light source of absolute distance interferometers. In our experiment, the methods for tuning frequency difference by rotating and applying a tunable force on the intracavity quartz plate are also studied.

  7. Analysis of gamma-ray damage to supercoiled DNA from electrooptical birefringence relaxation times

    International Nuclear Information System (INIS)

    Electrooptical birefringence (EO) measurements were performed on covalently closed, supercoiled Simian Virus 40 (SV40) DNA both in its native form, and after graded doses of 60Co γ-irradiation ranging from 2.5 to 104.6 Gy. Characteristic relaxation times are unchanged by γ-ray doses up to 105 Gy, and the subpopulation of molecules exhibiting the relaxation time tau1 also undergoes little change as a function of the absorbed radiation dose. However, the population parameter a2 decreases from approximately 50% to 40%, and a3 increases from 17% to 27% as the γ-ray dose is increased up to 50 Gy. The increase in the fraction of DNA molecules exhibiting the longest relaxation time would be expected insofar as the accumulation of radiation damage produces a progressively larger number of double-strand breaks, with a resultant increase in the number of linear molecules. 2 references, 1 figure

  8. Optical Search for QED vacuum magnetic birefringence, Axions and photon Regeneration

    CERN Multimedia

    Srnka, A; Pugnat, P; Hryczuk, A; Slunecka, M; Jary, V; Finger, M; Finger, M; Kral, M

    2007-01-01

    Since its prediction in 1936 by Euler, Heisenberg and Weisskopf in the earlier development of the Quantum Electrodynamic (QED) theory, the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology techniques. According to QED, the vacuum behaves as an optically active medium in the presence of an external magnetic field. It can be experimentally probed with a linearly polarized laser beam. After propagating through the vacuum submitted to a transverse magnetic field, the polarization of the laser beam will change to elliptical and the parameters of the polarization are directly related to fundamental constants such as the fine structure constant and the electron Compton wavelength. Contributions to the VMB could also arise from the existence of light scalar or pseudo-scalar particles like axions that couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction. On one side, the interest in axion search, providing an answer to the strong-CP p...

  9. Weak-guidance-theory review of dispersion and birefringence management by laser inscription

    International Nuclear Information System (INIS)

    A brief review of laser inscription of micro- and nanophotonic structures in transparent materials is provided in terms of a compact and convenient formalism based on the theory of weak optical waveguides. We derive physically instructive approximate expressions allowing propagation constants of laser-inscribed micro- and nanowaveguides to be calculated as functions of the transverse waveguide size, refractive index step, and dielectric properties of the host material. Based on this analysis, we demonstrate that dispersion engineering capabilities of laser micromachining techniques are limited by the smallness of the refractive index step typical of laser-inscribed structures. However, a laser inscription of waveguides in pre-formed micro- and nanostructures suggests a variety of interesting options for a fine dispersion and birefringence tuning of small-size waveguides and photonic wires

  10. Optical feedback characteristics in a helium neon laser with a birefringent internal cavity

    Institute of Scientific and Technical Information of China (English)

    Mao Wei; Zhang Shu-Lian; Xu Ting; Wan Xin-Jun; Liu Gang

    2007-01-01

    The output characteristics of optical feedback in a helium-neon laser with a birefringent internal cavity are studied systematically in five different regions of the gain curve for the two orthogonally polarized modes. When the laser operates in the two end regions of the laser gain curve, one of the two orthogonally polarized modes will be a leading one in optical feedback. Strong mode competition can be observed. However, when the laser operates in the middle region of the laser gain curve, the two modes can oscillate equally with optical feedback. Besides the intensity of the two polarized lights, the total light intensity is also studied at the same time. M-shaped optical feedback curves are found. Particularly, when the average intensities of the two lights are comparable, the intensity modulation curve of the total light is doubled, which can be used to improve the resolution of an optical feedback system.

  11. A Stable Optical Trap from a Single Optical Field Utilizing Birefringence

    CERN Document Server

    Singh, Robinjeet; Cripe, Jonathan; Corbitt, Thomas

    2016-01-01

    We report a stable double optical spring effect in an optical cavity pumped with a single optical field that arises as a result of birefringence. One end of the cavity is formed by a multilayer Al$_{0.92}$Ga$_{0.08}$As/GaAs stack supported by a microfabricated cantilever, with a natural mode frequency of $274$ Hz. The optical spring shifts the resonance to $21$ kHz, corresponding to a suppression of low frequency vibrations by a factor of more than $10^{4}$. The stable nature of the optical trap allows the cavity to be operated without any external feedback and with only a single optical field incident.

  12. High-birefringence fiber loop mirror sensor using a WDM fused fiber coupler.

    Science.gov (United States)

    Passos, D J; Marques, Manuel J; Frazão, Orlando

    2013-08-01

    An intensity-based highly birefringent (Hi-Bi) fiber loop mirror (FLM) sensor is proposed which uses a wavelength-division multiplexing (WDM) fiber coupler. The effect of integrating the WDM coupler in a FLM configuration is first studied. A section of Hi-Bi (bow-tie) fiber of length 0.26 m is then placed in the fiber loop, making the spectral response of the device simultaneously dependent on the Hi-Bi fiber section and WDM coupler characteristics. When strain is applied to the sensing head, the spectral signal is modulated in amplitude, in contrast with the conventional Hi-Bi FLM sensors in which there are wavelength shifts. The sensor was characterized in strain and a sensitivity of (-2.2±0.4)×10(-3) με(-1) for a range of 300 με was attained. The self-referenced character of the sensor is noted. PMID:23903181

  13. Influence of stress birefringence on the performance of a FBG pressure sensor

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-liang; QIAO Xue-guang; ZHOU Hong; SHAO Min; WEI Ting; LIU Ying-gang; LI Ting

    2005-01-01

    The effects of using overall affix and two-spot affix between the FBG and underlay on the characteristics of the pressure sensors are compared both experimentally and theoretically.It is found that overall affix can produce large nonlinear effect on the characteristics of output of the sensors.The nonlinear effect caused by the expanded spectral width mainly due to the stress birefringence and the stress grads etc.The experimental result shows that the spectral width caused by using overall affix is 0.28 nm and the linearity can have up to 1.89% of increasing by using two-spot affix.The method of two-spot affix can improve response characteristics of the sensor which is benefit to achieve wavelength demodulation and to improve measurement precision.

  14. Optical birefringence of liquid crystals for label-free optical biosensing diagnosis

    Directory of Open Access Journals (Sweden)

    Nguyen TT

    2015-08-01

    Full Text Available Tan Tai Nguyen,1 Gyeo-Re Han,2 Chang-Hyun Jang,1,2 Heongkyu Ju1,3,4 1Department of Bionano Technology, 2Department of Nano-Chemistry, 3Department of Nano-Physics, Gachon University, Seongnam-City, 4Neuroscience Institute, Gil Hospital, Incheon, South Korea Purpose: We present a polarization-sensitive optical detection platform for label-free quantitative optical biosensing diagnosis using liquid crystals (LCs. This is capable of determining quantitatively the optical birefringence of optical cells containing LCs, whose orientation depends on the immobilized biomolecules.Patients and methods: This technique uses a polarization-dependent double-port detection without any polarizer at a single wavelength and removes the need of aligning optical cells of LCs in the azimuthal direction, with respect to the light path through the optical cell. Thus, this technique enables a stand-alone detection in a relatively compact format without an additional optical instrument, such as a retardation compensator, a Michael–Levy chart, and a spectrophotometer, in order to determine the optical birefringence quantitatively.Results: We demonstrate that bovine serum albumin immobilized on the gold surface of the cell hybrid interfaces that support both homeotropic and planar anchoring of LCs causes optical phase retardation change which can be determined quantitatively. We also provide estimation of the zenithal orientation of LCs near the gold surface of the hybrid interfaces, based on the phase retardation determined. The estimated limit of bovine serum albumin detection is approximately 2.1 µM.Conclusion: This optical technique with LCs can serve an optical platform for label-free quantitative diagnosis of proteins in a real time manner. Keywords: biological sensors, LC orientation, protein sensing, tag-free diagnosis

  15. Probing vacuum birefringence under a high-intensity laser field with gamma-ray polarimetry at the GeV scale

    CERN Document Server

    Nakamiya, Yoshihide; Moritaka, Toseo; Seto, Keita

    2015-01-01

    Probing vacuum structures deformed by high intense fields is of great interest in general. In the context of quantum electrodynamics (QED), the vacuum exposed by a linearly polarized high-intensity laser field is expected to show birefringence. We consider the combination of a 10 PW laser system to pump the vacuum and 1 GeV gamma-rays to probe the birefringent effect. The vacuum birefringence can be measured via the polarization flip of the probe gamma-rays. We discuss the design of the gamma-ray polarimeter and then evaluate the measurability of the reduction of the degree of linear polarization due to the appearance of birefringence. We found that the measurement is indeed feasible given a realistic set of laser parameters and achievable pulse statistics.

  16. Theory of the Sagnac's interferometer of low birefringence and twist fiber; Teoria del interferometro de Sagnac de fibra de baja birrefrigencia y torcida

    Energy Technology Data Exchange (ETDEWEB)

    Estudillo-Ayala, J. M.; Kuzin, E. A.; Ibarra-Escamilla, B. [Instituto Nacional de Astrofisica, Optica y Electronica, Puebla (Mexico); Rojas-Laguna, R. [Universidad de Guanajuato, Guanajuato (Mexico)

    2001-06-01

    The fibre Sagnac interferometer of low birefringence and twist in the lineal region is examined numerically, a method is shown to measure the birefringence in the fibers and rotation of the axes inside of the interferometer fibre loop. [Spanish] El interferometro de Sagnac de fibra de baja birrefrigencia y torcida en la region lineal es numericamente examinado, se muestra un metodo para medir la birrefrigencia en las fibras y rotacion de los ejes dentro de la fibra del lazo del interferometro.

  17. Orientational dynamics of ferrofluids with finite magnetic anisotropy of the particles: relaxation of magneto-birefringence in crossed fields.

    Science.gov (United States)

    Raikher, Yu L; Stepanov, V I; Bacri, J-C; Perzynski, R

    2002-08-01

    Dynamic birefringence in a ferrofluid subjected to crossed bias (constant) and probing (pulse or ac) fields is considered, assuming that the nanoparticles have finite magnetic anisotropy. This is done on the basis of the general Fokker-Planck equation that takes into account both internal magnetic and external mechanical degrees of freedom of the particle. We describe the orientation dynamics in terms of the integral relaxation time of the macroscopic orientation order parameter. To account for an arbitrary relation between the bias (external) and anisotropy (internal) fields, an interpolation expression for the integral relaxation time is proposed and justified. A developed description is used to interpret the measurements of birefringence relaxation in magnetic fluids with nanoparticles of high (cobalt ferrite) and low (maghemite) anisotropy. The proposed theory appears to be in full qualitative agreement with all the experimental data available. PMID:12241160

  18. Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses

    Energy Technology Data Exchange (ETDEWEB)

    Amjad, Jafar Mostafavi; Khalesifard, Hamid Reza [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), 45137-66731 Zanjan (Iran, Islamic Republic of); Slussarenko, Sergei; Karimi, Ebrahim; Santamato, Enrico [Dipartimento di Scienze Fisiche, Universita di Napoli ' ' Federico II' ' , Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); Marrucci, Lorenzo [Dipartimento di Scienze Fisiche, Universita di Napoli ' ' Federico II' ' , Complesso Universitario di Monte S. Angelo, 80126 Napoli (Italy); CNR-SPIN, Complesso di Monte S. Angelo, 80126 Napoli (Italy)

    2011-07-04

    Samples of Ag{sup +}/Na{sup +} ion-exchanged glass that have been subject to intense laser irradiation may develop novel optical properties, as a consequence of the formation of patterns of silver nanoparticles and other structures. Here, we report the observation of a laser-induced permanent transverse birefringence, with the optical axis forming a radial pattern, as revealed by the spin-to-orbital angular momentum conversion occurring in a probe light beam. The birefringence pattern can be modeled well as resulting from thermally-induced stresses arising in the silver-doped glass during laser exposure, although the actual mechanism leading to the permanent anisotropy is probably more complex.

  19. Domain switching emission from the mixed-mode crack in ferroelectrics by birefringence measurement and phase field modeling

    Science.gov (United States)

    Li, Qun; Pan, Suxin; Liu, Qida; Wang, Jie

    2016-07-01

    The spatial and temporal evolution of domain switching near the tip of a mixed-mode crack (e.g., an inclined crack) is observed in ferroelectrics. The birefringence technique is used to measure the optical quantities to demonstrate the domain switching near the crack tip. The results show an intriguing feature that there appears electrical creep and domain switching emission from the crack tip. The actual time-dependence of domain switching emission and its anisotropic velocity is approximately measured. Moreover, the phase field modeling is developed to simulate polarization distribution and domain switching near the crack tip where the time-dependent Ginzburg–Landau equation is used to describe the change of polarization. The phase field results indicate the same features of domain switching emission from the mixed-mode crack. A good agreement between phase field simulation and birefringence measurement is concluded by setting the appropriate kinetic coefficient in the time-dependent Ginzburg–Landau equation.

  20. The use of Lorentz group formalism in solving polarization effects of a birefringent single mode optical fiber

    International Nuclear Information System (INIS)

    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. A Kind of Double-Cladding Photonic Crystal Fiber with High Birefringence and Two Zero-Dispersion Wavelengths

    Science.gov (United States)

    Zhou, Hong-Song; Li, Shu-Guang; Fu, Bo; Yao, Yan-Yan; Zhang, Lei

    2010-01-01

    A kind of double-cladding photonic crystal fiber (DC-PCF) with high birefringence and two zero-dispersion wavelengths is proposed. It is found that the birefringence of DC-PCF with inner cladding air holes pitch 1.0 μm and diameter 0.8 μm is 1.001 × 10-2 in the optical communication band at wavelength 1.55 μm by the multipole method. It is demonstrated that two zero dispersion wavelengths can be achieved in the optical communication band between 0.8 μm and 1.7 μm, and the first zero-dispersion wavelength is in the working wave band of the Ti:sapphire oscillator, which contributes to the frequency conversion of the Ti:sapphire femtosecond laser. PCF with two zero-dispersion wavelengths can make strong power supercontinuum spectral in the near infrared band.

  2. A scatterometry based CD metrology solution for advanced nodes, including capability of handling birefringent layers with uniaxial anisotropy

    Science.gov (United States)

    Ke, Chih-Ming; Hu, Jimmy; Wang, Willie; Huang, Jacky; Chung, H. L.; Liang, C. R.; Shih, Victor; Liu, H. H.; Lee, H. J.; Lin, John; Fan, Y. D.; Yen, Tony; Wright, Noelle; Alvarez Sanchez, Ruben; Coene, Wim; Noot, Marc; Yuan, Kiwi; Wang, Vivien; Bhattacharyya, Kaustuve; van der Mast, Karel

    2009-03-01

    A brand new CD metrology technique that can address the need for accuracy, precision and speed in near future lithography is probably one of the most challenging items. CDSEMs have served this need for a long time, however, a change of or an addition to this traditional approach is inevitable as the increase in the need for better precision (tight CDU budget) and speed (driven by the demand for increase in sampling) continues to drive the need for advanced nodes. The success of CD measurement with scatterometry remains in the capability to model the resist grating, such as, CD and shape (side wall angle), as well as the under-lying layers (thickness and material property). Things are relatively easier for the cases with isotropic under-lying layers (that consists of single refractive or absorption indices). However, a real challenge to such a technique becomes evident when one or more of the under-lying layers are anisotropic. In this technical presentation the authors would like to evaluate such CD reconstruction technology, a new scatterometry based platform under development at ASML, which can handle bi-refringent non-patterned layers with uniaxial anisotropy in the underlying stack. In the RCWA code for the bi-refringent case, the elegant formalism of the enhanced transmittance matrix can still be used. In this paper, measurement methods and data will be discussed from several complex production stacks (layers). With inclusion of the bi-refringent modeling, the in-plane and perpendicular n and k values can be treated as floating parameters for the bi-refringent layer, so that very robust CD-reconstruction is achieved with low reconstruction residuals. As a function of position over the wafer, significant variations of the perpendicular n and k values are observed, with a typical radial fingerprint on the wafer, whereas the variations in the in-plane n and k values are seen to be considerably lower.

  3. Influence of the strength of polarizing electric field on free relaxation of electric birefringence in poly(butyl-isocyanate) solutions

    Science.gov (United States)

    Tsvetkov, N. V.; Mikhailova, M. E.; Lebedeva, E. V.; Lezov, A. A.; Rogozhin, V. B.; Rotinyan, T. A.

    2016-03-01

    Free relaxation of electric birefringence in tetrachloromethane solution of high molecular weight poly(butyl-isocyanate) was studied. The effect of electric field strength on the average relaxation time was observed. The relaxation spectrum was analyzed using the Rouse and Zimm theories. With increase in the electric field strength, the contribution of fast (deformation) relaxation modes also increased significantly. It is assumed that certain changes in intramolecular mobility occur under the influence of electric field.

  4. A universal compensator for polarization changes induced by non-reciprocal circular birefringence on a retracing beam

    Science.gov (United States)

    Martinelli, Mario; Martelli, Paolo; Fasiello, Annalaura

    2016-05-01

    In this communication we recognize that it is possible to cancel out the effects of the non-reciprocal circular birefringence on a retracing beam. The experimental results demonstrate that a linearly polarized beam is returned into an orthogonal state after retracing through a variable Faraday rotator, by exploiting the reflective action of a Porro prism with edge at 45° with respect to the initial polarization axis, for any amount of non-reciprocal Faraday rotation.

  5. A simple structure of all circular-air-holes photonic crystal fiber for achieving high birefringence and low confinement loss

    International Nuclear Information System (INIS)

    We propose a simple structure of photonic crystal fibers (PCFs) with high birefringence and low confinement loss based on one rectangular centric ring of smaller circular air holes (CAHs) in the fiber core, and three rings of larger CAHs in the fiber cladding. This simple geometry (using all CAHs with two different air hole sizes) is capable of achieving a flexible control of the birefringence, B = 5.501 × 10−3, and ultra-low confinement loss, 7.30 × 10−5 dB/km, at an excitation wavelength of λ = 1550 nm. The birefringence value is ∼5.0 times greater than that obtained for conventional CAH PCF. This simple structure has the added advantage from the view point of easy fabrication, robustness, and cost. A full-vector finite element method combined with anisotropic perfectly matched layers was used to analyze the various fiber structures. We have analyzed four cases of CAH PCFs, focusing on the core asymmetry design as opposed to the conventional approach of CAHs or elliptical air holes on the cladding and core. The robustness against manufacturing inaccuracies of the proposed structure has also been further investigated in this work

  6. Theoretical analysis of the background intensity distribution in X-ray Birefringence Imaging using synchrotron bending-magnet radiation

    Science.gov (United States)

    Sutter, John P.; Dolbnya, Igor P.; Collins, Stephen P.; Harris, Kenneth D. M.; Edwards-Gau, Gregory R.; Palmer, Benjamin A.

    2015-04-01

    In the recently developed technique of X-ray Birefringence Imaging, molecular orientational order in anisotropic materials is studied by exploiting the birefringence of linearly polarized X-rays with energy close to an absorption edge of an element in the material. In the experimental setup, a vertically deflecting high-resolution double-crystal monochromator is used upstream from the sample to select the appropriate photon energy, and a horizontally deflecting X-ray polarization analyzer, consisting of a perfect single crystal with a Bragg reflection at Bragg angle of approximately 45°, is placed downstream from the sample to measure the resulting rotation of the X-ray polarization. However, if the experiment is performed on a synchrotron bending-magnet beamline, then the elliptical polarization of the X-rays out of the electron orbit plane affects the shape of the output beam. Also, because the monochromator introduces a correlation between vertical position and photon energy to the X-ray beam, the polarization analyzer does not select the entire beam, but instead selects a diagonal stripe, the slope of which depends on the Bragg angles of the monochromator and the polarization analyzer. In the present work, the final background intensity distribution is calculated analytically because the phase space sampling methods normally used in ray traces are too inefficient for this setup. X-ray Birefringence Imaging data measured at the Diamond Light Source beamline B16 agree well with the theory developed here.

  7. Exploiting the relationship between birefringence and force to measure airway smooth muscle contraction with PS-OCT (Conference Presentation)

    Science.gov (United States)

    Adams, David C.; Hariri, Lida P.; Holz, Jasmin A.; Szabari, Margit V.; Harris, R. Scott; Cho, Jocelyn L.; Hamilos, Daniel L.; Luster, Andrew D.; Medoff, Benjamin D.; Suter, Melissa J.

    2016-03-01

    The ability to observe airway dynamics is fundamental to forming a complete understanding of pulmonary diseases such as asthma. We have previously demonstrated that Optical Coherence Tomography (OCT) can be used to observe structural changes in the airway during bronchoconstriction, but standard OCT lacks the contrast to discriminate airway smooth muscle (ASM) bands- ASM being responsible for generating the force that drives airway constriction- from the surrounding tissue. Since ASM in general exhibits a greater degree of birefringence than the surrounding tissue, a potential solution to this problem lies in the implementation of polarization sensitivity (PS) to the OCT system. By modifying the OCT system so that it is sensitive to the birefringence of tissue under inspection, we can visualize the ASM with much greater clarity and definition. In this presentation we show that the force of contraction can be indirectly measured by an associated increase in the birefringence signal of the ASM. We validate this approach by attaching segments of swine trachea to an isometric force transducer and stimulating contraction, while simultaneously measuring the exerted force and imaging the segment with PS-OCT. We then show how our results may be used to extrapolate the force of contraction of closed airways in absence of additional measurement devices. We apply this technique to assess ASM contractility volumetrically and in vivo, in both asthmatic and non-asthmatic human volunteers.

  8. A simple structure of all circular-air-holes photonic crystal fiber for achieving high birefringence and low confinement loss

    Energy Technology Data Exchange (ETDEWEB)

    Chou Chau, Yuan-Fong, E-mail: chou.fong@ubd.edu.bn; Lim, Chee Ming; Yoong, Voo Nyuk; Syafi' ie Idris, Muhammad Nur [Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong BE1410, Brunei (Brunei Darussalam)

    2015-12-28

    We propose a simple structure of photonic crystal fibers (PCFs) with high birefringence and low confinement loss based on one rectangular centric ring of smaller circular air holes (CAHs) in the fiber core, and three rings of larger CAHs in the fiber cladding. This simple geometry (using all CAHs with two different air hole sizes) is capable of achieving a flexible control of the birefringence, B = 5.501 × 10{sup −3}, and ultra-low confinement loss, 7.30 × 10{sup −5 }dB/km, at an excitation wavelength of λ = 1550 nm. The birefringence value is ∼5.0 times greater than that obtained for conventional CAH PCF. This simple structure has the added advantage from the view point of easy fabrication, robustness, and cost. A full-vector finite element method combined with anisotropic perfectly matched layers was used to analyze the various fiber structures. We have analyzed four cases of CAH PCFs, focusing on the core asymmetry design as opposed to the conventional approach of CAHs or elliptical air holes on the cladding and core. The robustness against manufacturing inaccuracies of the proposed structure has also been further investigated in this work.

  9. Detecting vacuum birefringence with x-ray free electron lasers and high-power optical lasers: a feasibility study

    Science.gov (United States)

    Schlenvoigt, Hans-Peter; Heinzl, Tom; Schramm, Ulrich; Cowan, Thomas E.; Sauerbrey, Roland

    2016-02-01

    We study the feasibility of measuring vacuum birefringence by probing the focus of a high-intensity optical laser with an x-ray free electron laser (XFEL). This amounts to performing a new type of QED precision experiment, employing only laser pulses, hence space- and time-dependent fields. To set the stage, we briefly review the status of QED precision tests and then focus on the example of vacuum birefringence. Adopting a realistic laser beam model in terms of pulsed Gaussian beams we calculate the induced phase shift and translate it into an experimental signal, counting the number of photons with flipped polarization. We carefully design a detailed experiment at the European XFEL operating in self-seeded mode, supplemented by a petawatt class optical laser via the HIBEF project. Assuming all components to represent the current state of the art, in particular the x-ray polarizers, realistic estimates of signal-to-noise ratios plus ensuing acquisition times are provided. This is accompanied by a statistical analysis of the impact of poor laser focus overlap either due to timing and pointing jitter as well as limited alignment accuracy. A number of parasitic effects are analyzed together with appropriate countermeasures. We conclude that vacuum birefringence can indeed be measured upon combining an XFEL with a high-power optical laser if depolarization effects in the x-ray lenses can be controlled.

  10. Chemical and biological sensors based on optically confined birefringent chalcopyrite heterostructures

    International Nuclear Information System (INIS)

    This paper introduces and discusses the design and application(s) of a new and unique integrated solid-state molecular sensor (SSMS) system. The SSMS is based on optically confined birefringent heterostructure technology, which has the capability of recognizing target chemicals and biological molecules in an ambient environment. The SSMS technology is applicable for miniaturized sensor devices that can be used for quick, remote screening and recognition of chemical hazards in the environment. For example, trace impurities related to air/water pollution can be continuously monitored. Just as important, however, the SSMS technology will have a worldwide impact--economically as well as technologically--when used in the detection of chemical and biological agents, as well as for a variety of medical sensing applications, such as to identify and monitor complex biological structures, test for allergic reactions and screen for common diseases. Moreover, it could hasten the time of development and introduction into the marketplace of critically needed new drugs by the monitoring of biochemical and molecular cellular responses to the candidate drugs. Materials selection criteria, growth parameters and device architecture requirements are given and discussed. In addition, the results of a recent phase matching calculation, substantiating the feasibility of the SSMS, are given and discussed

  11. Maxwell's field coupled nonminimally to quadratic torsion: Induced axion field and birefringence of the vacuum

    CERN Document Server

    Itin, Y; Itin, Yakov; Hehl, Friedrich W.

    2003-01-01

    We consider a possible (parity conserving) interaction between the electromagnetic field $F$ and a torsion field $T^\\alpha$ of spacetime. For generic elementary torsion, gauge invariant coupling terms of lowest order fall into two classes that are both nonminimal and {\\it quadratic} in torsion. These two classes are displayed explicitly. The first class of the type $\\sim F T^2$ yields (undesirable) modifications of the Maxwell equations. The second class of the type $\\sim F^2 T^2$ doesn't touch the Maxwell equations but rather modifies the constitutive tensor of spacetime. Such a modification can be completely described in the framework of metricfree electrodynamics. We recognize three physical effects generated by the torsion: (i) An axion field that induces an {\\em optical activity} into spacetime, (ii) a modification of the light cone structure that yields {\\em birefringence} of the vacuum, and (iii) a torsion dependence of the {\\em velocity of light.} We study these effects in the background of a Friedman...

  12. Interrogation and mitigation of polarization effects for standard and birefringent FBGs

    Science.gov (United States)

    Ibrahim, Selwan K.; Van Roosbroeck, Jan; O'Dowd, John A.; Van Hoe, Bram; Lindner, Eric; Vlekken, Johan; Farnan, Martin; Karabacak, Devrez M.; Singer, Johannes M.

    2016-05-01

    Optical sensors based on Fiber Bragg Gratings (FBGs) are used in several applications and industries. Several inscription techniques and type of fibers can be used. However, depending on the writing process, type of fiber used and the packaging of the sensor a Polarization Dependent Frequency Shift (PDFS) can often be observed with polarized tunable laser based optical interrogators. Here we study the PDFS of the FBG peak for the different FBG types. A PDFS of 20pm was observed across the FBGs. To mitigate and reduce this effect we propose a polarization mitigation technique which relies on a synchronous polarization switch to reduce the effect typically by a factor greater than 4. In other scenarios the sensor itself is designed to be birefringent (Bi-FBG) to allow pressure and/or simultaneous temperature and strain measurements. Using the same polarization switch we demonstrate how we can interrogate the Bi-FBGs with high accuracy to enable high performance of such sensors to be achievable.

  13. Broadband optical gain in the normally dispersive region of a high-birefringence photonic crystal fiber

    International Nuclear Information System (INIS)

    Based on a designed high-birefringence photonic crystal fiber (HB-PCF) with two zero-dispersion wavelengths (ZDWs), the effect of pump parameters and Raman scattering on the modulation instability (MI) gain is comprehensively analyzed in this paper. An interesting result is found, in that only when the pump wavelength lies within an approximately 10 nm range of the zero-dispersion points in the normal dispersion region of the HB-PCF does a broadband gain characteristic appear. The Raman effect results in a combination of the gain spectra from the Stokes and anti-Stokes band, which finally promotes the formation of broadband amplification. Moreover, there exist an optimal pump wavelength and a suitable pump power along the fast axis or the slow axis of the fiber. With these optimal pump parameters, the total MI gain bandwidth finally reaches 159 nm for the fiber fast axis and 162 nm for the fiber slow axis. (paper)

  14. Fluctuations of cosmological birefringence and the effect on CMB B-mode polarization

    CERN Document Server

    Zhao, Wen

    2014-01-01

    The cosmological birefringence caused by the coupling between the cosmic scalar field and the cosmic microwave background (CMB) photons through the Chern-Simons term can rotate the polarization planes of the photons, and mix the CMB E-mode and B-mode polarizations. The rotation angle induced by the dynamical scalar field can be separated into the isotropic background part and the anisotropic fluctuations. The effect of the background part has been be studied in the previous work (Zhao & Li, arXiv:1402.4324). In this paper, we focus on the influence of the anisotropies of the rotation angle. We find that, if the cosmic scalar field is identified as the quintessence field, the anisotropies of the rotation angle are always too small to be detectable. However, if the scalar field is massless, the rotation spectrum can be quite large, which may be detected by the potential CMB observations. In addition, we find that, the rotated B-mode polarization could be fairly large, and comparable with those generated by ...

  15. Measurements of vacuum magnetic birefringence using permanent dipole magnets: the PVLAS experiment

    CERN Document Server

    Della Valle, F; Messineo, G; Milotti, E; Pengo, R; Piemontese, L; Ruoso, G; Zavattini, G

    2013-01-01

    The PVLAS collaboration is presently assembling a new apparatus (at the INFN section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB is related to the structure of the QED vacuum and is predicted by the Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by measuring the ellipticity acquired by a linearly polarised light beam propagating through a strong magnetic field. Using the very same optical technique it is also possible to search for hypothetical low-mass particles interacting with two photons, such as axion-like (ALP) or millicharged particles (MCP). Here we report results of a scaled-down test setup and describe the new PVLAS apparatus. This latter one is in construction and is based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity ($>4\\times 10^5$) and two 0.8 m long 2.5 T rotating permanent dipole magnets. Measurements with the test setup have improved by a factor 2 the previous upper bound on the parameter $A_e$, which determines the s...

  16. Narrow band pass filter using birefringence film and quarter-wave film

    Science.gov (United States)

    Lee, Dong-kun; Song, Jang-Kun

    2016-03-01

    While a pixel in a color image has three colorimetric information of RGB, that in a spectral image contains full spectral information, several tens times more information compared to the color image. Hence, the spectral image is widely applicable in biology, material science, and environmental science. Although several methods for spectral image acquisition have been suggested to date, those methods are expensive, bulky, or slow in actual device. In this work, we designed a novel type of tunable narrow band-pass filter using rotatable polarizer, quarter-wave plate, and birefringence films. Different from the conventional Lyot-Ohman type filter, we do not use a liquid crystal layer. The selection of wavelength is made by rotating the polarizer in our filter set, and adopted a piezoelectric rotational actuator for that. We simulated to find the optimal conditions of the filter set, and finally, fabricated a filter module. The minimum band width was 5 nm, which is suitable for usual spectral imaging and can be reduced further if necessary, and the wavelength of light passing through the filter set was continuously selectable. After setting the filter in a microscope, we obtained a spectral image set for a bio sample that contained full spectrum information in each pixel. Using image processing, we could demonstrate to read out the spectral information for any selected position.

  17. Polycyanurate ester resins with low loss and low birefringence for use in integrated optics

    Science.gov (United States)

    Dreyer, Christian J.; Bauer, Monika; Bauer, Joerg; Keil, Norbert; Yao, HuiHai; Zawadzki, Crispin

    2001-12-01

    In the age of information society and internet the requirements of fast transfers of large data streams for different applications are growing day by day. Killer-applications like teleconferencing, video-on-demand, online-games, virtual reality etc. are waiting in the wings. The optical network technology using the great bandwidth of glass fibre is the most suitable technology for these demands. Not only glass fibre is required, but also a broad range of optical components, such as multiplexers, demultiplexers, optical switches, optical attenuators, splitters and combiners, which are usually produced in silica technology. Polymeric materials are becoming more and more interesting for these applications, since they promise for instance lower power consumption and a reduction of production costs compared to their silica based pendants. Polycyanurate ester resins are a relatively new class of high-performance polymers with outstanding properties, for example high thermal stability, low optical loss, low dielectric constant, good adhesion and outstanding mechanical properties. This paper focuses on optical loss and birefringence of such materials at 1550 nm. The results lead the way to optimization for use in integrated optics and for the production of embedded waveguides and devices.

  18. Kinetic Monte Carlo simulations for birefringence relaxation of photo-switchable molecules on a surface

    Science.gov (United States)

    Tavarone, Raffaele; Charbonneau, Patrick; Stark, Holger

    2016-03-01

    Recent experiments have demonstrated that in a dense monolayer of photo-switchable dye methyl-red molecules the relaxation of an initial birefringence follows a power-law decay, typical for glass-like dynamics. The slow relaxation can efficiently be controlled and accelerated by illuminating the monolayer with circularly polarized light, which induces trans-cis isomerization cycles. To elucidate the microscopic mechanism, we develop a two-dimensional molecular model in which the trans and cis isomers are represented by straight and bent needles, respectively. As in the experimental system, the needles are allowed to rotate and to form overlaps but they cannot translate. The out-of-equilibrium rotational dynamics of the needles is generated using kinetic Monte Carlo simulations. We demonstrate that, in a regime of high density and low temperature, the power-law relaxation can be traced to the formation of spatio-temporal correlations in the rotational dynamics, i.e., dynamic heterogeneity. We also show that the nearly isotropic cis isomers can prevent dynamic heterogeneity from forming in the monolayer and that the relaxation then becomes exponential.

  19. Research on the detection system of liquid concentration base on birefringence light transmission method

    Science.gov (United States)

    Li, Tianze; Zhang, Xia; Hou, Luan; Jiang, Chuan

    2010-10-01

    The characteristics of the beam transmitting in the optical fiber and the liquid medium are analyzed in this paper. On this basis, a new type of semiconductor optical position sensitive detector is used for a receiving device, a light transmission method of birefringence is presented,and a set of opto-electrical detection system which is applied to detect liquid concentration is designed. The system is mainly composed of semiconductor lasers,optical systems, Psd signal conditioning circuit, Single-chip System, A/D conversion circuit and display circuit. Through theoretical analysis and experimental simulations, the accuracy of this system has been verified. Some main factors affecting the test results are analyzed detailedly in this paper. The experiments show that the temperature drift and the light intensity have a very small impact on this system. The system has some advantages, such as the simple structure, high sensitivity, good stability, fast response time, high degree of automation, and so on. It also can achieve the real-time detection of liquid concentration conveniently and accurately. The system can be widely applied in chemical, food, pharmacy and many other industries. It has broad prospects of application.

  20. Vacuum birefringence in strong magnetic fields: (I) Photon polarization tensor with all the Landau levels

    International Nuclear Information System (INIS)

    Photons propagating in strong magnetic fields are subject to a phenomenon called the “vacuum birefringence” where refractive indices of two physical modes both deviate from unity and are different from each other. We compute the vacuum polarization tensor of a photon in a static and homogeneous magnetic field by utilizing Schwinger’s proper-time method, and obtain a series representation as a result of double integrals analytically performed with respect to proper-time variables. The outcome is expressed in terms of an infinite sum of known functions which is plausibly interpreted as summation over all the Landau levels of fermions. Each contribution from infinitely many Landau levels yields a kinematical condition above which the contribution has an imaginary part. This indicates decay of a sufficiently energetic photon into a fermion–antifermion pair with corresponding Landau level indices. Since we do not resort to any approximation, our result is applicable to the calculation of refractive indices in the whole kinematical region of a photon momentum and in any magnitude of the external magnetic field. - Highlights: ► Vacuum birefringence is studied in the presence of externally applied magnetic field. ► A general framework is given on the basis of a vacuum polarization tensor of photon. ► A resummed vacuum polarization tensor is calculated analytically and exactly. ► Contributions of all the Landau levels are obtained in the form of an infinite sum. ► Threshold behavior of real-photon decay is obtained at the each Landau level.

  1. Host inflammatory response to polypropylene implants: insights from a quantitative immunohistochemical and birefringence analysis in a rat subcutaneous model

    Science.gov (United States)

    Prudente, Alessandro; Fávaro, Wágner José; Latuf, Paulo; Riccetto, Cássio Luis Zanettini

    2016-01-01

    ABSTRACT Objectives To describe acute and sub acute aspects of histological and immunohistochemical response to PP implant in a rat subcutaneous model based on objective methods. Materials and Methods Thirty rats had a PP mesh subcutaneously implanted and the same dissection on the other side of abdomen but without mesh (sham). The animals were euthanized after 4 and 30 days. Six slides were prepared using the tissue removed: one stained with hematoxylin-eosin (inflammation assessment); one unstained (birefringence evaluation) and four slides for immunohistochemical processing: IL-1 and TNF-α (pro-inflammatory cytokines), MMP-2 (collagen metabolism) and CD-31 (angiogenesis). The area of inflammation, the birefringence index, the area of immunoreactivity and the number of vessels were objectively measured. Results A larger area of inflammatory reaction was observed in PP compared to sham on the 4th and on the 30th day (p=0.0002). After 4 days, PP presented higher TNF (p=0.0001) immunoreactivity than sham and no differences were observed in MMP-2 (p=0.06) and IL-1 (p=0.08). After 30 days, a reduction of IL-1 (p=0.010) and TNF (p=0.016) for PP and of IL-1 (p=0.010) for sham were observed. Moreover, area of MMP-2 immunoreactivity decreased over time for PP group (p=0.018). Birefringence index and vessel counting showed no differences between PP and sham (p=0.27 and p=0.58, respectively). Conclusions The implantation of monofilament and macroporous polypropylene in the subcutaneous of rats resulted in increased inflammatory activity and higher TNF production in the early post implant phase. After 30 days, PP has similar cytokines immunoreactivity, vessel density and extracellular matrix organization. PMID:27286125

  2. Linear birefringence and dichroism measurement in oil-based Fe{sub 3}O{sub 4} magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jing-Fung, E-mail: jacklin@cc.feu.edu.tw [Graduate School of Computer Application Engineering, Far East University, Tainan 74448, Taiwan (China); Wang, Chia-Hung [Department of Automation and Control Engineering, Far East University, Tainan 74448, Taiwan (China); Lee, Meng-Zhe [Graduate School of Computer Application Engineering, Far East University, Tainan 74448, Taiwan (China)

    2013-04-15

    To prepare dispersed Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs), we adopt a co-precipitation method and consider surfactant amount, stirring speed, dispersion mode, and molar ratio of Fe{sup 3+}/Fe{sup 2+}. Via transmission electronic microscopy and X-ray diffractometry, we characterize the dispersibility and size of the products and determine the appropriate values of experimental parameters. The stirring speed is 1000 rpm in titration. There is simultaneous ultrasonic vibration and mechanical stirring in the titration and surface coating processes. The surfactant amount of oleic acid is 1.2 ml for molar ratios of Fe{sup 3+}/Fe{sup 2+} as 1.7:1, 1.8:1, and 1.9:1. The average diameters of these Fe{sub 3}O{sub 4} MNPs are 11 nm, and the ratios of saturation magnetization for these MNPs to that of bulk magnetite range from 45% to 65%, with remanent magnetization close to zero and low coercivity. Above all, the linear birefringence and dichroism measurements of the kerosene-based ferrofluid (FF) samples are investigated by a Stokes polarimeter. The influences of particle size distribution and magnetization in the birefringence and dichroism measurements of FFs are discussed. - Highlights: ► Dispersed Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs) are produced by a co-precipitation method. ► Simultaneous ultrasonic vibration and mechanical stirring are used in titration and coating. ► Diameters of Fe{sub 3}O{sub 4} MNPs are determined as 11 nm with maximum magnetization as 54.27 emu/g. ► Birefringence and dichroism of ferrofluids are obtained by a Stokes polarimeter successfully.

  3. Physical description of statistical hypothesis testing for a weak-value amplification experiment using a birefringent crystal

    OpenAIRE

    Susa, Yuki

    2015-01-01

    We investigate the weak measurement experiment demonstrated by Ritchie et al. [N. W. M. Ritchie, J. G. Story, and R. G. Hulet, Phys. Rev. Lett. 66, 1107 (1991)] from the viewpoint of the statistical hypothesis testing for the weak-value amplification proposed by Susa and Tanaka [Y. Susa and S. Tanaka, Phys. Rev. A 92, 012112 (2015)]. We conclude that the weak-value amplification is a better method to determine whether the crystal used in the experiment is birefringent than the measurement wit...

  4. Development of simultaneous measurement system of birefringence, optical rotational power, and transmission spectra for chiral liquid crystal phases

    Science.gov (United States)

    Feng, Zhengyu; Ishikawa, Ken

    2016-05-01

    A novel experimental setup used to measure the important optical properties of liquid crystal materials is proposed. The setup allows us to measure electric-field-induced birefringence, optical rotational power, and transmission spectra consecutively. This system can be widely applied to characterize liquid crystal materials including blue phases, ferroelectric liquid crystals, and other chiral phases. We adopted this system to study the phase transition behavior of a V-shape switching ferroelectric liquid crystal mixture and made an important correction of experimental results previously reported by Sandhya et al. [ Europhys. Lett. 90, 56005 (2010)]. This finding proves the advantage of this system compared with the measurement method using individual systems.

  5. Optimization of wavefront distortions and thermal-stress induced birefringence in a cryogenically-cooled multislab laser amplifier

    Czech Academy of Sciences Publication Activity Database

    Slezák, Ondřej; Lucianetti, Antonio; Divoký, Martin; Sawicka, Magdalena; Mocek, Tomáš

    2013-01-01

    Roč. 49, č. 11 (2013), s. 960-966. ISSN 0018-9197 R&D Projects: GA MŠk ED2.1.00/01.0027; GA MŠk EE2.3.20.0143 Grant ostatní: HILASE(XE) CZ.1.05/2.1.00/01.0027; OP VK 6(XE) CZ.1.07/2.3.00/20.0143 Institutional support: RVO:68378271 Keywords : birefringence * YAG lasers * thermooptic effects * multislab laser amplifier * cryogenic Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.113, year: 2013

  6. Characterization of polarizer made of the deep-UV birefringent crystal Ba2Mg(B3O6)2.

    Science.gov (United States)

    Zhao, Jing; Ma, Yingying; Li, Rukang

    2015-11-20

    In optical communications and the laser industry, modulating the polarization of light requires crystals with both large birefringence and a wide transparent range. A good candidate for a deep-UV birefringent crystal is Ba2Mg(B3O6) because it has a large birefringence and short UV cutoff edge. We grew Ba2Mg(B3O6)2 crystals with sizes up to 41  mm×40  mm×7  mm using the top-seeded solution growth method. We obtained the thermal-expansion coefficients in different directions and the thermo-optic coefficients and then designed and manufactured a Glan-Taylor type polarizer to fulfill the commercial requirements. PMID:26836562

  7. An Optical 2×4 90° Hybrid Based on a Birefringent Crystal for a Coherent Receiver in a Free-Space Optical Communication System

    Institute of Scientific and Technical Information of China (English)

    HOU Pei-Pei; ZHI Ya-Nan; ZHOU Yu; SUN Jian-Feng; LIU Li-Ren

    2011-01-01

    The design and fabrication of an optical 2 × 4 90° hybrid based on birefringent crystals for a coherent receiver in a free-space optical communication system are presented.For the quadrature receiver,two pairs of 180° phaseshift outputs are obtained and one pair has a phase difference of 90° with respect to the other.The 90° hybrid comprises two pairs of stacked birefringent plates,a phase retardation plate and an analyser birefringent plate.The testing results measured by the heterodyne method verify that the 2 × 4 optical 90° hybrid can work correctly and effectively.The phase compensation and further optimization schemes are also proposed.

  8. Model and Simulation of a Tunable Birefringent Fiber Using Capillaries Filled with Liquid Ethanol for Magnetic Quasiphase Matching In-Fiber Isolator

    Directory of Open Access Journals (Sweden)

    Clint Zeringue

    2010-01-01

    Full Text Available A technique to tune a magnetic quasi-phase matching in-fiber isolator through the application of stress induced by two mutually orthogonal capillary tubes filled with liquid ethanol is investigated numerically. The results show that it is possible to “tune” the birefringence in these fibers over a limited range depending on the temperature at which the ethanol is loaded into the capillaries. Over this tuning range, the thermal sensitivity of the birefringence is an order-of-magnitude lower than conventional fibers, making this technique well suited for magnetic quasi-phase matching.

  9. Mueller matrix analysis for all optical fiber co-existence of birefringence-polarization dependent gain-mode coupling at a single wavelength

    Institute of Scientific and Technical Information of China (English)

    Shang Chio; Wu Chong-Qing; Li Zheng-Yong; Yang Shuang-Shou; Gao Kai-Qiang; Yu Kuang-Lu; Feng Zhen

    2011-01-01

    Birefringence (polarization-related phase-shift),polarization dependent gain (PDG) and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers.This paper obtains a new Mueller matrix analysis,which can be used under conditions that all these three factors are existing and changing.According to our transmission model,the state of polarization (SOP) changes along an optical microstructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results,which show the phenomena of SOP constringency,are in good agreement with previous theoretical analyses.

  10. A new approach to polarimetric measurements based on birefringent crystals and diode lasers

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Lívia Paulia Dias; Rohwedder, Jarbas José Rodrigues [Chemistry Institute, Department of Analytical Chemistry, UNICAMP, Caixa Postal 6154, CEP: 13087-971 Campinas, SP (Brazil); Pasquini, Celio, E-mail: pasquini@iqm.unicamp.br [Chemistry Institute, Department of Analytical Chemistry, UNICAMP, Caixa Postal 6154, CEP: 13087-971 Campinas, SP (Brazil)

    2013-04-10

    Highlights: ► New approach to polarimetric measurements is evaluated. ► A robust, with no mechanical moving parts polarimeter is presented. ► The performance of the instrument was evaluated for saccharimetric measurements. ► The uncertainty of the instrument was evaluated as a function of the measured angle. ► Polarimeter allow the use of low cost lasers while obtaining precision as good as 0.003°. -- Abstract: A new polarimetric instrument and measurement method is described based on the use of diode lasers as radiation source (532, 650 and 1064 nm) and birefringent prisms, such as Glan-Laser and Wollaston, as analyzers. The laser radiation is passed through a dichroic polarizer film for further orientation of its polarization plane at 45° in relation to the polarization plane of the analyzer. The polarized beam, oriented in that way, passes the sample cell, impinges the prism surface, and the intensities of the two emerged beams are detected by two twin silicon detectors. Ideally, in the absence of any optically active substances, the crystals produces two orthogonally polarized refracted beams of equal intensity. In the presence of an optically active substance, the arctangent of the square root of the beam intensities ratio is equal to the new polarization angle (β) of the laser beam. The rotation angle imposed for any optically active substance present in the sample cell is then given by: α = (45 – β)°. Because the rotation is obtained by the ratio of the intensities of two beams, it is independent of the laser intensity, which can vary up to ±15% with no significant effect on the accuracy of the polarimetric measurement. The instrument has been evaluated for measurement of optically active substances such as sucrose and fructose. The instrument employs low cost components, is capable of attaining a repeatability of ±0.003° and can measure the rotation angle, over a ±45° range, in less than 2 s. Because it does not present any moving

  11. Birefringence-induced frequency beating in high-finesse cavities by continuous-wave cavity ring-down spectroscopy

    Science.gov (United States)

    Dupré, Patrick

    2015-11-01

    By analyzing the decaying intensity, leaking out a high-finesse cavity previously "filled" by a cw laser source (using the cavity ring-down spectroscopy technique), we observed frequency beating between what we think are two orthogonal eigenpolarization states of the intracavity electromagnetic field. The time decay (ring down) is analyzed by varying the angle of the polarization analyzer located in front of the detector. A full modeling of the observed signal is proposed. It is based on the Jones matrix formalism required for modeling the cavity behavior following a rotated phase shifter. The full transfer function is first established in the frequency domain, and then Fourier transformed to recover the temporal response. The same optical cavity, i.e., constituted of the same set of mirrors, is used at two different wavelengths (˜800 and ˜880 nm). It demonstrates the differences in behavior between a high-finesse cavity (˜400 000 ) and a lower finesse cavity (˜50 000 ). Beating frequency, characteristics time, and beat amplitude are mainly discussed versus the analyzer angle. A cavity birefringence of ˜1.6 ×10-5 rad, resulting from the mirror birefringence is suggested. If the current analysis is in agreement with pulsed CRDS experiments (polarimetry) obtained in an isotropic moderate-finesse cavity, it differs from a recent work report on a high-finesse cavity associated with a source mode locking [Phys. Rev. A 85, 013837 (2012), 10.1103/PhysRevA.85.013837].

  12. Patterns of cellulose microfibril deposition and rearrangement in Nitella: in vivo analysis by a birefringence index. [Nitella axillaris

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, P.A.

    1983-01-01

    The mean alignment of cellulose microfibrils in the wall of a living Nitella internode can be quantified by polarized light microscopy. Microfibrils within the cylindrical wall of a normal internode have a scattered but generally circumferential arrangement. The action of polarized light on such a wall creates a birefringent pattern that relates to microfibrillar organization, including the degree of microfibrillar scatter or mean angular dispersion. This pattern, quantified as a birefringence index (BRI), can be followed during the growth of an individual cell. Changes in the BRI reflect shifts in the patterns of either microfibril deposition, microfibril rearrangements during growth, or both. This diagnostic capability has allowed the dynamics of the following events to be examined in vivo: response of microfibril deposition to addition and removal of antimicrotubule drugs, multinet growth under various conditions of cell expansion, and cellulose synthesis inhibition. This work has shown that cellulose microfibril synthesis is not coupled to cell expansion in Nitella and that the directionality of cell expansion is governed by only an inner portion of the cell wall. 31 references, 7 figures, 1 table.

  13. Sensing and transmission characteristics of a rocking filter fabricated in a side-hole fiber with zero group birefringence.

    Science.gov (United States)

    Anuszkiewicz, A; Martynkien, T; Mergo, P; Makara, M; Urbanczyk, W

    2013-05-20

    We report on sensing and transmission characteristics of rocking filters fabricated in a silica side-hole fiber with group birefringence changing its sign at certain wavelength (λ(G = 0)), which corresponds to parabolic-like spectral dependence of beat length. Unusual birefringence dispersion of the side-hole fiber is induced by an elliptical germanium doped core located in a narrow glass bridge between two holes. Rocking filters fabricated in such a fiber have two resonances of the same order located on both sides of λ(G = 0). The sensitivity of both resonances has an opposite sign, which makes it possible to double the response of the rocking filter by applying the differential interrogation scheme. We demonstrate that in this way a pressure sensitivity of the rocking filter can be enlarged to 132 nm/MPa. We also show that by fabricating the rocking filter with a period close to maximum beat length a coupling between polarization modes can be obtained in a broad band reaching 240 nm. PMID:23736486

  14. Hong-Ou-Mandel interference experiment of two independent heralded single photon sources in an optical fiber with birefringence

    Science.gov (United States)

    Ma, Tianyi; Zhou, Qiang; Zhang, Wei; Huang, Yidong; Cui, Xiaowei; Lu, Mingquan; Feng, Zhenming

    2012-11-01

    Single photon sources (SPSs) play important roles in quantum communication and quantum information processing. Spontaneous four wave mixing (SFWM) in optical fibers provides a promising way to realize practical heralded single photon sources (HSPSs), since it is compatible with current techniques of optical communications. In this paper, two independent HSPSs at 1.5μm band are realized in one polarization maintaining dispersion shifted fiber (PM-DSF) utilizing its large birefringence. When pulsed pump light passes through an optical fiber, two kinds of SFWM will take place simultaneously. One is scalar processes, in which two annihilated pump photons and generated photon pair are all polarized along the same fiber polarization axis. The other is vector processes, in which two annihilated pump photons are polarized along different fiber polarization axes, either for the two photons of the generated pair. In the PM-DSF, the large birefringence generates obvious walk-off effect on the two pump polarization components, which leads to an effective suppression of the vector processes. Hence, by proper pump polarization, correlated photon pairs (CPPs) with different polarization directions can be generated independently by the two scalar processes, which can be used to realize two independent HSPSs. The indistinguishability of the heralded photons generated by the two independent sources is demonstrated by an experiment of Hong-Ou-Mandel (HOM) interference. Using a fiber coupler as the beam splitter, a visibility of HOM dip of 76% is achieved, showing their potential on quantum information.

  15. Follow-up on deformation by cold rolling and on recrystallization with birefringence and poisson module as determined by ultrasound

    International Nuclear Information System (INIS)

    Since the speed of propagation of ultrasonic waves in elastic materials is directly related to their elastic constants, these velocities can be matched with a materials' degree of anisotropy. The ultrasonic technique normally used to evaluate the degree of anisotropy is acoustic birefringence, which in the case of rolled materials arises from the difference between the elastic constants C44 and C55, and what is measured as the difference in velocities between two perpendicularly polarized cut waves traveling through the thickness of the sample over the average of both. The main advantage comes from there being a ratio between velocities in a single running space, so this is cancelled, eliminating the need to measure the thickness. In an isotropic C44 = C55 material, the velocities of the wave sections are independent of the direction of polarization, so birefringence is zero. The degree of anisotropy, then is quantified as the level of deviance from zero in the value of the birefringence. The cold rolling of a metal sheet induces a degree of orthotropy that can be reverted with a thermal recrystallization treatment. Meanwhile, the Poisson module is measured based on the ratio between the velocity of a longitudinal wave and a cut wave running along the same space, so the value of the thickness is also omitted. Since the speed of the short wave in an isotropic material does not depend on its direction of polarization, the value of the Poisson module does not depend on it either, and in the case of an anisotropic material it obviously does. This work proposes, then, to use the Poisson module to follow the evolution of the anisotropy in ASTM A-36 steel veneers cold rolled at different degrees of deformation and then submitted to thermal austenization treatments. To investigate the effects of the tests deformation processes were designed for 5% to 50% lamination and thermal treatments at 900oC to 1000oC to study the variations in wave velocities and in the materials

  16. The lone-pairs enhanced birefringence and SHG response: A DFT investigation on M2B5O9Cl (M = Sr, Ba, and Pb)

    International Nuclear Information System (INIS)

    Highlights: • Enhanced birefringence and SHG response of Pb2B5O9Cl comparison with its isostructural M2B5O9Cl. • The enhancement originates from the covalent interaction of Pb and O atoms. • The interaction of Pb–O reduces the bandgap comparison with its isostructural M2B5O9Cl. - Abstract: It is important to investigate the electronic structures and optical properties of the UV NLO compound containing lone-pairs electrons, aiming to make a subtle balance among relative large SHG response, big birefringence and deep bandgap. In this paper, the electronic structures and optical properties of M2B5O9Cl (M = Sr, Ba, and Pb) have been investigated using the DFT method. The results show that the enhanced birefringence and SHG response are found in Pb2B5O9Cl comparison with that of Sr2B5O9Cl and Ba2B5O9Cl. And the enhanced birefringence and SHG response in Pb2B5O9Cl originate from the covalent interaction between the oxygen and lead atoms

  17. Utility of birefringence changes due to collagen thermal denaturation rate process analysis: vessel wall temperature estimation for new short term heating balloon angioplasty

    Science.gov (United States)

    Kaneko, Kenji; Shimazaki, Natsumi; Gotoh, Maya; Nakatani, Eriko; Arai, Tsunenori

    2007-02-01

    Our photo thermal reaction heating architecture balloon realizes less than 10 s short term heating that can soften vessel wall collagen without damaging surrounding tissue thermally. New thermal balloon angioplasty, photo-thermo dynamic balloon angioplasty (PTDBA) has experimentally shown sufficient opening with 2 atm low pressure dilation and prevention of chronic phase restenosis and acute phase thrombus in vivo. Even though PTDBA has high therapeutic potential, the most efficient heating condition is still under study, because relationship of treatment and thermal dose to vessel wall is not clarified yet. To study and set the most efficient heating condition, we have been working on establishment of temperature history estimation method from our previous experimental results. Heating target of PTDBA, collagen, thermally denatures following rate process. Denaturation is able to be quantified with measured collagen birefringence value. To express the denaturation with equation of rate process, the following ex vivo experiments were performed. Porcine extracted carotid artery was soaked in two different temperature saline baths to enforce constant temperature heating. Higher temperature bath was set to 40 to 80 degree Celsius and soaking duration was 5 to 40 s. Samples were observed by a polarizing microscope and a scanning electron microscope. The birefringence was measured by polarizing microscopic system using Brace-Koehler compensator 1/30 wavelength. The measured birefringence showed temperature dependency and quite fit with the rate process equation. We think vessel wall temperature is able to be estimated using the birefringence changes due to thermal denaturation.

  18. A projection operator approach for computing the dynamics of AS2S3 chalcogenide birefringent photonic crystal fiber coupler

    Science.gov (United States)

    Uthayakumar, T.; Vasantha Jayakantha Raja, R.; Porsezian, K.

    2015-02-01

    A variety of AS2S3 chalcogenide photonic crystal fiber coupler of special properties are proposed to study the role of birefringence in all optical coupling characteristics based on the projection operator method (POM). The equations of motion describing the dynamics of the individual pulse parameters through x- and y-polarized modes are arrived at by employing POM from the coupled nonlinear Schrödinger equations. From the pulse parameter dynamics, it is observed that the amplitudes of the polarization components are significantly influenced by the pulse being introduced with different polarizing angle even at low input power level. Such a selective polarizing angles of the input pulse will provide efficient control over the desired splitting ratio as well as the ability to decide the desired polarization component.

  19. Generation of tailored pulse trains for efficient material processing by a high power MOPA system with birefringence compensation

    International Nuclear Information System (INIS)

    A flash lamp pumped, acousto-optical Q-switched Nd:YAG master oscillator power amplifier (MOPA) system with an average output power of almost 150 W and a beam quality of M2 < 2.5 is developed. The system operates with a 100 Hz repetition rate for the flash lamps. In each pumping pulse a pulse train of 5 to 40 Q-switched laser pulses is generated. The pulse length is from 25 to 150 ns. A high beam quality of the amplified beam is realized by an elaborate amplifier design and a careful alignment of the beam diameter to the amplifier rods. Additionally, the thermally induced birefringence of the amplifiers is compensated by a 90° rotator and an optical image-relay system between two identical amplifier rods, so that a linear polarized laser beam could be achieved with depolarization losses below 2%

  20. Influence of operating temperature on the power, divergence, and stress-induced birefringence in solar-pumped solid state lasers

    Science.gov (United States)

    Brauch, U.; Muckenschnabel, J.; Thompson, George A.; Bernstein, Hana; Yogev, Amnon; Reich, A.; Oron, Moshe

    1992-05-01

    The relative performance of solar-pumped Nd:YAG and Nd:Cr:GSGG lasers was evaluated at both 300 and 80 K. Measurements of the slope efficiency and the lasing threshold were made on several lasers containing these crystals. The stress-induced birefringence and the divergence were also studied. The measurements were used to calculate the values of the intrinsic efficiencies and the losses at both temperatures. The possible mechanisms for the observed temperature dependence are discussed. Due to the improved thermal conductivity of the laser crystals at low temperature, all lasers showed significantly improved performance at low temperature. Both the slope efficiencies and the thresholds improved by a factor of 2 to 3 on cooling. The absolute value of the beam quality, and its sensitivity to changes in the resonator configuration or pump power were significantly better at low temperature.

  1. Dynamic compensation of thermal lensing and birefringence in a high-brightness Nd:Cr:GSGG oscillator

    Science.gov (United States)

    Moshe, Inon; Jackel, Steven M.; Lallouz, Raphael; Tzuk, I.

    1997-09-01

    In this work, five fundamental concepts were combined to a low development of high efficiency, low divergence, narrow bandwidth, flashlamp pumped oscillators capable of operation over a broad operating range. These concepts were: flashlamp pumped Nd:Cr:GSGG to achieve high efficiency, a 'Reentrant Cavity' to eliminate birefringence losses, a variable radius back mirror in a hemispherical cavity to achieve maximum Gaussian beam fill factor, a very high damage threshold, spectrum narrowing output coupler fabricated using a stack of uncoated etalons to form a resonant reflector, a cylindrical zoom lens to completely eliminate astigmatism. The results were successful, and yielded an oscillator that produced 10 mJ, TEM00 300 MHz bandwidth, 75 ns pulses, over a repetition rate of 1-20 Hz, and at a slope efficiency of 2 percent. These techniques were also successfully applied to a YLF oscillator. They may, in part, be adapted for use to unstable resonators.

  2. Precision Controlling of Frequency Difference for Elastic-Stress Birefringence He-Ne Dual-Frequency Lasers

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lu-Fei; ZHANG Shu-Lian; GUO Hong; REN Zhou

    2007-01-01

    Birefringence-Zeeman dual frequency lasers are capable of producing frequency difference from several kilohertz to hundreds of megahertz, but the precision of giving and stabilizing of the beat frequency still needs improvement to the range of ±200 kHz. We design a new elastic force-exerting device comprised of the bottom part, two arms and two pieces of force-exerting sheets. The frequency difference smoothly tuning is realized with this device in a large range of 2 MHz to 20 MHz. Power-balance frequency stabilization system is used to investigate characters of the temperature, frequency difference and laser power. The precision of the frequency difference has reach up to JrlOO kHz after system temperature balance. Analyses of the laser frequency difference and power character are carried out.

  3. Generation of radially and azimuthally polarized beams in Yb:YAG laser with intra-cavity lens and birefringent crystal.

    Science.gov (United States)

    Thirugnanasambandam, Manasadevi P; Senatsky, Yuri; Ueda, Ken-ichi

    2011-01-31

    We demonstrated the operation of cw diode-pumped Yb:YAG laser in radial or azimuthal polarized (RP or AP) beams using a combination of birefringent uniaxial crystal (c-cut YVO4 or α-BBO) and lens as intra-cavity elements. RP and AP doughnut modes (M2 = 2-2.5, polarization extinction ratio 50-100:1) with output power up to 60 mW were generated. Apart from doughnut modes, RP or AP ring-like off-axis oscillations and multi-ring beams with mixed RP and AP were also observed at the output of this laser scheme. Using intra-cavity short focus lenses with spherical aberrations AP or RP modes of higher orders was obtained. Mechanism of mode selection in the laser is discussed. The large variety of beams with axially symmetric polarizations from the output of the proposed laser scheme may find applications in different fields. PMID:21369005

  4. Superior electro-optical properties of electrically controlled birefringence mode using solution-derived La2O3 films

    International Nuclear Information System (INIS)

    The authors demonstrate a high performance electrically controlled birefringence (ECB) mode with solution-derived La2O3 films at various molar concentrations. Uniform and homogeneous liquid crystal (LC) alignment was spontaneously achieved on the La2O3 films for lanthanum concentrations at ratios greater than and equal to 0.2. A preferred orientation of LC molecules appeared along the filling direction, and the LC alignment was maintained via van der Waals force by nanocrystals of the La2O3 films. The LC alignment mechanism was confirmed by x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. Superior electro-optical characteristics of the ECB cells constructed with solution-derived La2O3 films were observed, which suggests that the proposed solution-derived La2O3 films have strong potential for use in the production of advanced LC displays

  5. Spontaneous birefringence of flux grown single crystals of the ferroelectric/antiferromagnetic perovskite lead iron tantalate (PbFe1/2Ta1/2O3) (PFT)

    OpenAIRE

    Brixel, Wolf Dietrich; Rivera, Jean-Pierre; Schmid, Hans

    1984-01-01

    The spontaneous birefringence Δns of the rhombohedral ferroelectric phase of PFT has been measured between 20 K and the hitherto unknown first order transition at 210 K (heating)/205 K (cooling). Above that transition there is a weakly birefringent phase, which undergoes a second order transition to cubic at ∼248 K. Pronounced photoconductivity occurs below room temperature. A strong reversible temperature shift (-5.7 cm-1 K-1) of the absorption edge obscures the material upon heating.

  6. Specific heat and linear birefringence behaviour of 4-aminopyridinium tetrachloroantimonate (III), [4-NH2C5H4NH][SbCl4

    International Nuclear Information System (INIS)

    Thermal (specific heat) and optical (linear birefringence) studies were performed for a new ferroelectric crystal [4-NH2C5H4NH][SbCl4]. Four phase transitions were confirmed and described. Thermal parameters (ΔH, ΔS) of the normal-incommensurate, N-IC, and incommensurate-ferroelectric commensurate, IC-F(C), phase transitions are given. The order-disorder mechanism of the N-IC phase transition is proved but the displacive one for the IC-F(C) transition can be proposed. The critical index value (2β = 0.68 ± 0.02) estimated from the linear birefringence measurements indicates that the N-IC phase transition can be described in terms of the 3d XY model. (letter to the editor)

  7. LETTER TO THE EDITOR: Specific heat and linear birefringence behaviour of 4-aminopyridinium tetrachloroantimonate (III), [4-NH2C5H4NH][SbCl4

    Science.gov (United States)

    Przeslawski, J.; Kosturek, B.; Jakubas, R.

    2003-11-01

    Thermal (specific heat) and optical (linear birefringence) studies were performed for a new ferroelectric crystal [4-NH2C5H4NH][SbCl4]. Four phase transitions were confirmed and described. Thermal parameters (DgrH,DgrS) of the normal-incommensurate, N-IC, and incommensurate-ferroelectric commensurate, IC-F(C), phase transitions are given. The order-disorder mechanism of the N-IC phase transition is proved but the displacive one for the IC-F(C) transition can be proposed. The critical index value (2bgr = 0.68 ± 0.02) estimated from the linear birefringence measurements indicates that the N-IC phase transition can be described in terms of the 3d XY model.

  8. Thermal birefringence-compensated linear intracavity frequency doubled Nd:YAG rod laser with 73 ns pulse duration and 160Wgreen output power

    Indian Academy of Sciences (India)

    S K Sharma; A J Singh; P K Gupta; P Hedaoo; P K Mukhopadhyay; K Ranganathan; K S Bindra; S M Oak

    2014-02-01

    In a thermally birefringence-compensated linear cavity configuration, ∼160 W of average green power by intracavity frequency doubling of AO Q-switched Nd:YAG/LBO-based laser is demonstrated. The corresponding optical to optical conversion efficiency is estimated to be ∼12.7%. The pulse repetition rate is 20 kHz with the individual pulse duration of 73 ns. The beam quality parameter is measured to be 18.

  9. Performance Analysis of High-speed Optical Pulse Transmission in Dispersion-managed Nonlinear Birefringent Fiber Using Quantum Well Laser Diode Sources

    Institute of Scientific and Technical Information of China (English)

    YAN Minhui; CHEN Jianping

    2002-01-01

    This paper analyzes the high bit-rate optical pulse trasmission in single mode optical fiber with chromatic dispersion, polarization mode dispersion (small random birefringence) and nonlinearity. Numerical method employed can precisely describe their interactive effect on transmission performance. Different dispersion maps and the related performance are analysed. Various simulation results and discussion are given. The results show that chromatic dispersion compensation should be carefully designed. Appropriate dispersion management can also alleviate the effect of polarization mode dispersion.

  10. A novel micro-processing of waveguide coupler in birefringent crystal by twin tracks of single-scan femtosecond laser writing

    Science.gov (United States)

    Cheng, Chen; Vázquez de Aldana, J. R.; Chen, Feng

    2015-07-01

    Through a novel micro-processing mechanism in birefringent crystals proposed in this work, a coupler containing twin depressed cladding waveguides have been achieved in Nd:GdVO4 laser crystals. By employing single-scan of femtosecond laser writing, twin tracks with different depths separated by a distance of 70μm were produced due to the birefringence of Nd:GdVO4 crystal. The adjacent 30μm-diameter cladding waveguides, which consist of a 2×2 coupler with a separation of 70μm in a 4-mm-long crystal sample, were inscribed simultaneously. The ratio of output power division from both waveguides was approximately 10.5:1 at 633nm. Continuous-wave lasing was realized in the waveguide coupler platform under the direct optical pump at 808nm. This work indicates a great potential for femtosecond laser inscribed symmetry structures such as waveguide couplers in birefringent crystals based on the proposed micro-processing mechanism.

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

    International Nuclear Information System (INIS)

    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. (paper)

  12. Azo polymers with electronical push and pull structures prepared via RAFT polymerization and its photoinduced birefringence behavior

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Two methacrylate monomers containing azo and electronical push and pull structure, e.g. 2-Methyl-acrylic-acid-2-{[4-(4-cyano-phenylazo-3-methyl-phenyl]-ethyl-amino-ethyl ester (MACP with cyano substituted and 2-Methylacrylic-acid-2-{ethyl-[4-(4-methoxy-phenylazo-3-methyl-phenyl]-amino}-ethyl ester (MAMP with methoxy substituted, were synthesized and polymerized using 2-cyanoprop-2-yl dithiobenzoate (CPDB as chain transfer agent and 2,2'-azobisisobutyronitrile (AIBN as initiator. The results showed that the polymerization displayed characteristics of ‘living’/controlled free radical polymerization. Thus, the obtained polymers, polyMACP (pMACP and polyMAMP (pMAMP, had controlled molecular weights and narrow molecular weights distribution. The chain extension experiments of pMACP and pMAMP using styrene as the second monomer were successfully carried out. The photo-induced trans-cis-trans isomerization kinetic of pMACP and pMAMP in chloroform solution were described. Marked differences in rate for the trans-cis and cis-trans isomerization of pMACP and pMAMP were observed in chloroform solution due to the different electronic effects in these two polymers. Photoinduced birefringence and surface relief grating (SRG of the pMACP and pMAMP were investigated in thin film state.

  13. Experimental observation of multiple dispersive waves emitted by multiple mid-infrared solitons in a birefringence tellurite microstuctured optical fiber.

    Science.gov (United States)

    Cheng, Tonglei; Tuan, Tong Hoang; Xue, Xiaojei; Liu, Lai; Deng, Dinghuan; Suzuki, Takenobu; Ohishi, Yasutake

    2015-08-10

    We experimentally demonstrate multiple dispersive waves (DWs) emitted by multiple mid-infrared solitons in a birefringence tellurite microstuctured optical fiber (BTMOF). To the best of our knowledge, this is the first demonstration of multiple DWs in the non-silica fibers. By using a pulse of ~80 MHz and ~200 fs emitted from an optical parametric oscillator (OPO) as the pump source, DWs and solitons are investigated on the fast and slow axes of the BTMOF at the pump wavelength of ~1800 nm. With the average pump power increasing from ~200 to 450 mW, the center wavelength of the 1st DW decreases from ~956 to 890 nm, the 2nd DW from ~1039 to 997 nm, the 3rd DW from ~1101 to 1080 nm, and the 4th DW from ~1160 to 1150 nm. Meanwhile, obvious multiple soliton self-frequency shifts (SSFSs) are observed in the mid-infrared region. Furthermore, DWs and solitons at the pump wavelength of ~1400 and 2000 nm are investigated at the average pump power of ~350 mW. PMID:26367917

  14. Effect Terthiophenes Units on the Microstructure and Birefringence of SiO2 Gels Prepared via Sol-Gels Processing

    International Nuclear Information System (INIS)

    Materials ceramics products based on SiO2 gels have been produced via sol-gels processing in present of 1% NH4F/H2O as catalyst. Alkoxysilane from tetraethoxysilane (TEOS) are chose as a matrices or template sources, than the product's of syntheses precursor: 2,5-bis(trimethoxysilyl)terthiophene (BTS3T) used as a motif organic compound: That product formed matrices as silicate backbone of terthiophene-briged silsesquioxane net-work; [O1.5Si-(C4H2S)n-SiO1.5]n. The structure silsesquioxane terthiophene-briged formed have layer distance of 4.6and 8.6 angstroms. So, that terthiophenes units in their structure give an effect on the characteristic pattern as an ordered micro lamellar structure. Electron microscopy analyses in matrices -Si-O-Si- there spheres formed by diameter about 10 μm which are rich in silicon. The effect of terthiophenes unites on SiO2 gels formed shown that birefringence phenomenas are strong in presence of higher quantity oligothiophenes units, and will decrease with increase quantity of alkoxysilane, with anisotropic values differences decrease every 1.125 x 10-3 per mole SiO2, whereas the optical transparency of SiO2 gels formed are increase

  15. Linear birefringence and dichroism in citric acid coated Fe{sub 3}O{sub 4} magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jing-Fung, E-mail: jacklin@cc.feu.edu.tw [Graduate School of Computer Application Engineering, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan, Taiwan, ROC (China); Tsai, Chun-Chin [Department of Optoelectronic Engineering, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan, Taiwan, ROC (China); Lee, Meng-Zhe [Graduate School of Computer Application Engineering, Far East University, No. 49, Zhonghua Road, Xinshi District, Tainan, Taiwan, ROC (China)

    2014-12-15

    To prepare highly dispersed water-based Fe{sub 3}O{sub 4} magnetic nanoparticles (MNPs), we adopted the co-precipitation method and used citric acid (CA) as the surfactant. Via transmission electronic microscopy, dynamic light scattering, and X-ray diffractometry, we characterized the dispersibility and size of the products. Through two single-parameter experiments, including the pH value of suspension and the action of double centrifugations, the appropriate parameters' values were determined. Further, to produce CA coated MNPs with good magneto-optical properties as high retardance and low dichroism, the orthogonal design method was used to find the optimal parameters' values, including pH value of suspension after coating was 5, molar ratio of CA to Fe{sub 3}O{sub 4} MNPs was 0.06, volume of CA was 40 ml, and coating temperature was 70 °C. Above all, the linear birefringence and dichroism of the best CA coated ferrofluid we produced were measured by a Stokes polarimeter as 23.6294° and 0.3411 under 64.5 mT, respectively. Thus, the biomedical applications could be performed hereafter. - Highlights: • We examine pH changes about retardance/dichroism of citric acid coated ferrofluid. • We examine centrifugal action about dispersity of citric acid coated ferrofluid. • Dispersity of coated suspensions with different pH is investigated by DLS results. • Optimum combination and influence sequence obtained by Taguchi method is found. • Molar ratio of CA to Fe{sub 3}O{sub 4} deeply influences the retardance and dichroism of FFs.

  16. Measuring the wavelength of a diode laser and the birefringence of mica: the experimental examination of the IPHO 40 held in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Moran-Lopez, J L [Faculty of Science, Universidad Nacional Autonoma de Mexico (Mexico); OrtIz, M E; Romero-Rochin, V [Institute of Physics, Universidad Nacional Autonoma de Mexico (Mexico); RodrIguez, L F [Center for Radioastronomy and Astrophysics, Universidad Nacional Autonoma de Mexico (Mexico)

    2010-07-15

    The experimental examination applied in the 40th International Physics Olympiad held in Merida, Yucatan, Mexico, is presented. The examination consisted of two parts: (1) based on the measurements of a diffraction pattern produced by a diode laser impinging on a sharp edge of a razor blade, the students were asked to estimate the wavelength of the laser. (2) By using the same experimental setup, the contestants had to measure the birefringence of a mica film. For completeness, we give a brief description of the theoretical test. Finally, we present the distribution of marks and show, on the world map, with different colours, the performance of various countries.

  17. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide

    CERN Document Server

    Ciret, Charles

    2016-01-01

    The scattering of a linear wave on an optical event horizon, induced by a cross polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with co-polarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent on the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schr\\"odinger equations fully support the experimental results.

  18. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide.

    Science.gov (United States)

    Ciret, Charles; Gorza, Simon-Pierre

    2016-06-15

    The scattering of a linear wave on an optical event horizon, induced by a cross-polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with copolarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent of the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schrödinger equations fully support the experimental results. PMID:27304314

  19. Phenomenon of magnetic birefringence in solutions of paramagnetic substances. Communication 2. Molar-magneto-optic constants of chlorides and nitrates of some lanthanides in water

    International Nuclear Information System (INIS)

    This paper determines the molar constants of the magnetic birefringence of chlorides and nitrates of some lanthanides in water and extrapolates them to infinite dilution. The principal semiaxes of the optical-polarizability ellipsoids of hydrated rare-earth cations have been evaluated in the axial approximation. The magneto-optic properties of dilute solutions of lanthanide nitrates (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) are attributed to the constancy of the composition and structure of the aquo complexes with the participation of nitrate anions

  20. Birefringence imaging and orientation of laser patterned β-BaB2O4 crystals with bending and curved shapes in glass

    International Nuclear Information System (INIS)

    Nonlinear optical β-BaB2O4 crystals (β-BBO) with bending and curved shapes were patterned at the surface of 8Sm2O3–42BaO–50B2O3 glass by laser irradiations (Yb:YVO4 laser with a wavelength of 1080 nm, power of 0.8 W, and scanning speed of 4 μm/s), and the orientation state of β-BBO crystals was examined from the birefringence imaging obtained by polarization optical microscope (POM) observations. The formation (crystallization) of β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes at a certain point within the bending angle of 60°. The birefringence images indicate that the formation of highly c-axis oriented β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes, and in particular the direction of the c-axis of β-BBO crystals changes gradually at the bending point. The model for the orientation of the c-axis of β-BBO near the bending point is proposed. The present study proposes that the laser-induced crystallization opens a new door for the science and technology in crystal growth engineering. - Graphical abstract: This figure shows the birefringence images obtained by the Abrio IM imaging system (λ=546 nm) for the laser-patterned β-BaB2O4 crystal line with the bending angle of 45° in the glass. The relation between the direction of slow axis and color is also shown. It is demonstrated that the formation (crystallization) of highly c-axis oriented β-BaB2O4 crystals follows along laser scanning direction even if the laser scanning direction changes. Display Omitted - Highlights: • β-BaB2O4 crystals with bending and curved shapes were patterned by laser irradiations. • The orientation was examined from the birefringence imaging. • Highly c-axis oriented crystals follows along laser scanning direction. • The c-axis direction changes gradually at the bending point. • The laser-induced crystallization opens a new door in crystal growth engineering

  1. Scattering of a cross-polarized linear wave by a soliton at an optical event horizon in a birefringent nanophotonic waveguide

    Science.gov (United States)

    Ciret, Charles; Gorza, Simon-Pierre

    2016-06-01

    The scattering of a linear wave on an optical event horizon, induced by a cross polarized soliton, is experimentally and numerically investigated in integrated structures. The experiments are performed in a dispersion-engineered birefringent silicon nanophotonic waveguide. In stark contrast with co-polarized waves, the large difference between the group velocity of the two cross-polarized waves enables a frequency conversion almost independent on the soliton wavelength. It is shown that the generated idler is only shifted by 10 nm around 1550 nm over a pump tuning range of 350 nm. Simulations using two coupled full vectorial nonlinear Schr\\"odinger equations fully support the experimental results.

  2. Birefringence imaging and orientation of laser patterned β-BaB{sub 2}O{sub 4} crystals with bending and curved shapes in glass

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Kazuki; Honma, Tsuyoshi; Komatsu, Takayuki, E-mail: komatsu@mst.nagaokaut.ac.jp

    2013-11-15

    Nonlinear optical β-BaB{sub 2}O{sub 4} crystals (β-BBO) with bending and curved shapes were patterned at the surface of 8Sm{sub 2}O{sub 3}–42BaO–50B{sub 2}O{sub 3} glass by laser irradiations (Yb:YVO{sub 4} laser with a wavelength of 1080 nm, power of 0.8 W, and scanning speed of 4 μm/s), and the orientation state of β-BBO crystals was examined from the birefringence imaging obtained by polarization optical microscope (POM) observations. The formation (crystallization) of β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes at a certain point within the bending angle of 60°. The birefringence images indicate that the formation of highly c-axis oriented β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes, and in particular the direction of the c-axis of β-BBO crystals changes gradually at the bending point. The model for the orientation of the c-axis of β-BBO near the bending point is proposed. The present study proposes that the laser-induced crystallization opens a new door for the science and technology in crystal growth engineering. - Graphical abstract: This figure shows the birefringence images obtained by the Abrio IM imaging system (λ=546 nm) for the laser-patterned β-BaB{sub 2}O{sub 4} crystal line with the bending angle of 45° in the glass. The relation between the direction of slow axis and color is also shown. It is demonstrated that the formation (crystallization) of highly c-axis oriented β-BaB{sub 2}O{sub 4} crystals follows along laser scanning direction even if the laser scanning direction changes. Display Omitted - Highlights: • β-BaB{sub 2}O{sub 4} crystals with bending and curved shapes were patterned by laser irradiations. • The orientation was examined from the birefringence imaging. • Highly c-axis oriented crystals follows along laser scanning direction. • The c-axis direction changes gradually at the bending point. • The

  3. Effect of change in macular birefringence imaging protocol on retinal nerve fiber layer thickness parameters using GDx VCC in eyes with macular lesions.

    Science.gov (United States)

    Dada, Tanuj; Tinwala, Sana I; Dave, Vivek; Agarwal, Anand; Sharma, Reetika; Wadhwani, Meenakshi

    2014-08-01

    This study evaluates the effect of two macular birefringence protocols (bow-tie retardation and irregular macular scan) using GDx VCC on the retinal nerve fiber layer (RNFL) thickness parameters in normal eyes and eyes with macular lesions. In eyes with macular lesions, the standard protocol led to significant overestimation of RNFL thickness which was normalized using the irregular macular pattern protocol. In eyes with normal macula, absolute RNFL thickness values were higher in irregular macular pattern protocols with the difference being statistically significant for all parameters except for inferior average thickness. This has implications for monitoring glaucoma patients who develop macular lesions during the course of their follow-up. PMID:24469116

  4. Form birefringence analysis in a grating by means of modal theory; Analisis de la birrefringencia de forma en una rejilla mediante la teoria modal

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Ponce, G.; Solano, Cristina [Centro de Investigaciones en Optica A.C, Guanajuato (Mexico)

    2001-02-01

    The propagation of a plane electromagnetic wave through a grating using the modal theory is analyzed. The eigenproblem is solved in function of the ratio illumination wavelength {lambda} to grating period (d). When this ratio is much greater than one (quasiestatic limit), the grating shows a response similar to an uniaxial film. It is possible to approximate the eigenfunction for calculating the effective refractive indices of the birefringent element. This effect is called form birefringence and can be used to design retardation plates. [Spanish] En este trabajo se analiza la propagacion de una onda electromagnetica plana a traves de una rejilla utilizando la teoria modal. Estableciendo el problema de valor caracteristico se determina que la solucion es dependiente de la razon longitud de onda de iluminacion {lambda} y el periodo de la rejilla (d). En el caso {lambda}/d mayor que 1, conocido como el limite cuasiestatico, la rejilla se comporta como una pelicula uniaxial, obteniendose los indices ordinario y extraordinario a partir de una aproximacion a la ecuacion caracteristica. Este fenomeno, llamado birrefringencia de forma, puede emplearse para disenar elementos birrefringentes.

  5. Near-Field Birefringence Response of Liquid Crystal Molecules in Thickness Direction of Liquid Crystal Thin Film Orientated by Shear Force

    Institute of Scientific and Technical Information of China (English)

    Jing QIN; Norihiro UMEDA

    2007-01-01

    Information of molecular orientation in nematic liquid crystal (LC) is attractive and important for applications in the field of display devices. We demonstrate a novel method using a birefringence scanning near-field optical microscope (Bi-SNOM) with a probe which is inserted into the LC thin film to detect the molecular orientation from its birefringence responses in the thickness direction of the LC thin film. The probe is laterally vibrated when going forward into the LC thin film, and the retardation and azimuth angle are recorded as the probe going down. Firstly, the thickness of the LC thin film is measured by the shear force detection. Since the shear force acts as a stimulation to reorientate the LC molecules above the substrate surface, we can detect the molecular orientation caused by a polyimide alignment substrate and the effect to molecular orientation caused by vibration of fibre probe. As a result, the orientation profiling of the LC film in depth direction is obtained in both the cases that the direction of probe vibrating is vertical/parallel to the rubbing direction of the alignment film.Furthermore, the thickness of completely orientated layers just above the substrate surface can also be obtained by either vibrating probe or no-vibrating probe. Ultimately, the LC thin film can be modelled in thickness direction from all the results using this method.

  6. Fully vectorial laser resonator modeling of continuous-wave solid-state lasers including rate equations, thermal lensing and stress-induced birefringence.

    Science.gov (United States)

    Asoubar, Daniel; Wyrowski, Frank

    2015-07-27

    The computer-aided design of high quality mono-mode, continuous-wave solid-state lasers requires fast, flexible and accurate simulation algorithms. Therefore in this work a model for the calculation of the transversal dominant mode structure is introduced. It is based on the generalization of the scalar Fox and Li algorithm to a fully-vectorial light representation. To provide a flexible modeling concept of different resonator geometries containing various optical elements, rigorous and approximative solutions of Maxwell's equations are combined in different subdomains of the resonator. This approach allows the simulation of plenty of different passive intracavity components as well as active media. For the numerically efficient simulation of nonlinear gain, thermal lensing and stress-induced birefringence effects in solid-state active crystals a semi-analytical vectorial beam propagation method is discussed in detail. As a numerical example the beam quality and output power of a flash-lamp-pumped Nd:YAG laser are improved. To that end we compensate the influence of stress-induced birefringence and thermal lensing by an aspherical mirror and a 90° quartz polarization rotator. PMID:26367545

  7. Birefringence imaging and orientation of laser patterned β-BaB2O4 crystals with bending and curved shapes in glass

    Science.gov (United States)

    Ogawa, Kazuki; Honma, Tsuyoshi; Komatsu, Takayuki

    2013-11-01

    Nonlinear optical β-BaB2O4 crystals (β-BBO) with bending and curved shapes were patterned at the surface of 8Sm2O3-42BaO-50B2O3 glass by laser irradiations (Yb:YVO4 laser with a wavelength of 1080 nm, power of 0.8 W, and scanning speed of 4 μm/s), and the orientation state of β-BBO crystals was examined from the birefringence imaging obtained by polarization optical microscope (POM) observations. The formation (crystallization) of β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes at a certain point within the bending angle of 60°. The birefringence images indicate that the formation of highly c-axis oriented β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes, and in particular the direction of the c-axis of β-BBO crystals changes gradually at the bending point. The model for the orientation of the c-axis of β-BBO near the bending point is proposed. The present study proposes that the laser-induced crystallization opens a new door for the science and technology in crystal growth engineering.

  8. Near-elliptic core triangular-lattice and square-lattice PCFs: a comparison of birefringence, cut-off and GVD characteristics towards fiber device application

    CERN Document Server

    Maji, Partha Sona

    2014-01-01

    In this work, detailed numerical analysis of the near-elliptic core index-guiding triangular-lattice and square-lattice photonic crystal fiber (PCFs) are reported for birefringence, single mode, cut-off behavior, group velocity dispersion and effective area properties. For the same relative values of d/P, triangular-lattice PCFs show higher birefringence whereas the square-lattice PCFs show a wider range of single-mode operation. Square-lattice PCF was found to be endlessly single-mode for higher air-filling fraction (d/P). Smaller lengths of triangular-lattice PCF are required for dispersion compensation whereas PCFs with square-lattice with nearer relative dispersion slope (RDS) can better compensate the broadband dispersion. Square-lattice PCFs show ZDW red-shifted, making it preferable for mid-IR supercontinuum generation (SCG) with highly non-linear chalcogenide material. Square-lattice PCFs show higher dispersion slope that leads to compression of the broadband, thus accumulating more power in the pulse...

  9. Searching for minicharged particles via birefringence, dichroism and Raman spectroscopy of the vacuum polarized by a high-intensity laser wave

    International Nuclear Information System (INIS)

    Absorption and dispersion of probe photons in the field of a high-intensity circularly polarized laser wave are investigated. The optical theorem is applied for determining the absorption coefficients in terms of the imaginary part of the vacuum polarization tensor. Compact expressions for the vacuum refraction indices and the photon absorption coefficients are obtained in various asymptotic regimes of interest. The outcomes of this analysis reveal that, far from the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum are small and, in some cases, strongly suppressed. On the contrary, in a vicinity of the region in which the photo-production of a pair occurs, these optical properties are manifest with lasers of moderate intensities. We take advantage of such a property in the search of minicharged particles by considering high-precision polarimetric experiments. In addition, Raman-like electromagnetic waves resulting from the inelastic part of the vacuum polarization tensor are suggested as an alternative form for finding exclusion limits on these hypothetical charge carriers. The envisaged parameters of upcoming high-intensity laser facilities are used for establishing upper bounds on the minicharged particles. -- Highlights: •Via dichroism and birefringence of the vacuum by a strong laser wave, minicharged particles can be probed. •The discovery potential is the highest in a vicinity of the first pair production threshold. •As alternative observable, Raman scattered waves are put forward

  10. The lone-pairs enhanced birefringence and SHG response: A DFT investigation on M{sub 2}B{sub 5}O{sub 9}Cl (M = Sr, Ba, and Pb)

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Qun [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Department of Physics, School of Science, Shihezi University, Shihezi 832000 (China); Dong, Xiaoyu [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); Engineering Department of Chemistry and Environment, Xinjiang Institute of Engineering, 236 Nanchang Road, Urumqi 830091 (China); Chen, Xinglong [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Zhihua, E-mail: zhyang@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); Pan, Shilie, E-mail: slpan@ms.xjb.ac.cn [Key Laboratory of Functional Materials and Devices for Special Environments of CAS, Xinjiang Technical Institute of Physics & Chemistry of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, 40-1 South Beijing Road, Urumqi 830011 (China); and others

    2015-05-12

    Highlights: • Enhanced birefringence and SHG response of Pb{sub 2}B{sub 5}O{sub 9}Cl comparison with its isostructural M{sub 2}B{sub 5}O{sub 9}Cl. • The enhancement originates from the covalent interaction of Pb and O atoms. • The interaction of Pb–O reduces the bandgap comparison with its isostructural M{sub 2}B{sub 5}O{sub 9}Cl. - Abstract: It is important to investigate the electronic structures and optical properties of the UV NLO compound containing lone-pairs electrons, aiming to make a subtle balance among relative large SHG response, big birefringence and deep bandgap. In this paper, the electronic structures and optical properties of M{sub 2}B{sub 5}O{sub 9}Cl (M = Sr, Ba, and Pb) have been investigated using the DFT method. The results show that the enhanced birefringence and SHG response are found in Pb{sub 2}B{sub 5}O{sub 9}Cl comparison with that of Sr{sub 2}B{sub 5}O{sub 9}Cl and Ba{sub 2}B{sub 5}O{sub 9}Cl. And the enhanced birefringence and SHG response in Pb{sub 2}B{sub 5}O{sub 9}Cl originate from the covalent interaction between the oxygen and lead atoms.

  11. Optical single sideband modulation based on a high-order birefringent filter using cascaded Solc-Sagnac and Lyot-Sagnac loops.

    Science.gov (United States)

    Feng, Danqi; Sun, Junqiang

    2016-08-01

    We propose and experimentally demonstrate a simple and flexible photonic approach to implementing single sideband (SSB) modulation based on optical spectral filtering. The high-order birefringent filter is realized through the cascaded Solc-Sagnac and Lyot-Sagnac loops. By adjusting the rotation angle of the polarization controller (PC), the notch position to remove undesired sidebands changes. The frequency for SSB modulation varies accordingly. The periodical response of the filter spectrum allows both the carrier wavelength and the optical carrier to sideband ratio (OCSR) to be tunable. SSB modulation over a frequency range from 5 to 40 GHz and tunable OCSR ranging from -9.174 to 34.408 dB are obtained. The significant merits of the proposed approach are the simple structure, easy operation, large frequency range, tunable OCSR, and wavelength independence. The approach has potential applications in optimizing the transmission performance of photonic microwave signal processing systems. PMID:27472643

  12. Linear to radial/azimuthal polarization converter in transmission using form birefringence in a segmented silicon grating manufactured by high productivity microelectronic technologies

    Science.gov (United States)

    Kaempfe, T.; Sixt, P.; Renaud, D.; Lagrange, A.; Perrin, F.; Parriaux, O.

    2014-05-01

    A polarization rotation is realized by subwavelength binary gratings, where the TE and TM round trip phases of the smallest grating modes are fixed to the smallest possible integer numbers of 2π that allow a straight-through phase difference of π. This results in a subwavelength grating allowing to realize a half-wave element of almost 100% transmission. The principle is applied to a polarization transformation in the 1030-1064 nm wavelength range, using a segmented polarization rotating element converting a linearly polarized incidence to a radial or azimuthal polarization distribution. The elevated costs of such kind of polarization transformers based on assembled birefringent crystals are avoided by using mass-fabrication compatible silicon on insulator technology on a wafer scale. It shows the general potential of microelectronic technology, concerning the batch manufacturing of wavelength-scale diffractive, grating based elements for processing free space waves

  13. The fine structure of the vortex-beams in the biaxial and biaxially-induced birefringent media caused by the conical diffraction

    CERN Document Server

    Fadeyeva, Tatyana; Anischenko, Pavel; Volyar, Alexander

    2011-01-01

    We consider the paraxial propagation of nondiffracting singular beams inside natural biaxial and biaxially-induced birefringent media in vicinity of one of the optical axes in terms of eigenmode vortex-beams, whose angular momentum does not change upon propagation. We have predicted a series of new optical effects in the natural biaxial crystals such as the stable propagation of vector singular beams bearing the coupled optical vortices with fractional topological charges, the conversion of the zero-order Bessel beam with a uniformly distributed linear polarization into the radially-, azimuthally- and spirally-polarized beams and the conversion of the space-variant linear polarization in the combined beam with coupled vortices. We have revealed that the field structure of the vortex-beams in the biaxially-induced crystals resembles that in the natural biaxial crystals and form the vector structure inherent in the conical diffraction. However, the mode beams in this case do not change the propagation direction...

  14. Study of thermal effects, considering birefringence, on phase distortion of beam in a side pumped Nd:YAG rod using BEM

    Science.gov (United States)

    Sovizi, M.; Massudi, R.

    2007-07-01

    The present study uses boundary element method (BEM) in linear approximation to solve heat transfer equation. Differential equations of displacement are numerically solved through BEM to obtain strain tensor in an Nd:YAG crystal diode transversely pumped in a three fold geometry. Variation of refractive index, due to the temperature distribution and induced birefringence, which arises from photo-elastic effect, is obtained in the volume of the rod. Then the phase shift imposed on emerging beam from the rod is calculated by solving the equation of path of ray along the laser rod. Using the obtained results, effective focal distance and astigmatism of the beam for different types of polarization are calculated.

  15. A fast real time measurement system to track in and out of plane optical retardation/ birefringence, true stress, and true strain during biaxial stretching of polymer films

    Science.gov (United States)

    Cakmak, M.; Hassan, M.; Unsal, E.; Martins, C.

    2012-12-01

    An instrumented and highly integrated biaxial stretching system was designed and constructed to obtain true stress, true strain, and optical behavior of polymeric films during biaxial stretching. With programmable drive motors, any form of temporally varying biaxial deformation profiles, including linear, exponential, logarithmic as well as cyclic, can be applied to a square-shaped films. This machine allows the investigation of mechano-optical behavior of films under profiles captured in industrial processes. To overcome the edge effects, the samples are painted with a dot pattern that is imaged using a high speed video capture system. This system accurately determines the locations of the each dot matrix in subsequent images acquired and calculates the true strains in both directions. The in-plane optical retardation is determined using spectral birefringence method that uses polarized white light and optical spectrometer in the optical train. This is carried out automatically at less than 10 nm in retardation resolution with the light beam passing through the symmetry center of the sample. Out of plane retardation is measured with an identical optical train tilted 45° to the plane of the film with its light beam going through the same spot on the sample as 0° beam. The true stress and birefringences are calculated with the determined instantaneous thickness of the film. With this system, the stress optical behavior of PET's is determined up to very large deformation levels at moderate to high deformation rates. Beyond the initial linear stress optical behavior, these films exhibit sudden positive deviation from linearity and this start of nonlinearity was directly associated with the stress induced crystallization.

  16. Investigation on birefringence property in uniaxial crystal (Ca{sub 0.28}Ba{sub 0.72}){sub 0.75}(Sr{sub 0.60}Ba{sub 0.40})Nb{sub 2}O{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Xia, H.R. [School of Physics and Microelectronics of Shandong University, Jinan (China); State Key Laboratory of Crystal Materials, Shandong University, Jinan (China); Xu, J.Q.; Si, S.C. [School of Physics and Microelectronics of Shandong University, Jinan (China); Zhang, H.J.; Wang, J.Y. [Institute of Crystal Materials, Shandong University, Jinan (China); Gao, C.Y.

    2008-04-15

    The birefringence of (Ca{sub 0.28}Ba{sub 0.72}){sub 0.75}(Sr{sub 0.60}Ba{sub 0.40})Nb{sub 2}O{sub 6} crystal is measured basing on polarization- extinction method and conoscopic interference method. Experimental results show that the birefringence in this crystal is up to 10{sup -5}, the natural birefringence in this crystal is (n{sub o}-n{sub e})=5.89 x 10{sup -5} with the He-Ne laser wavelength at 632.8 nm and the birefringence grads with wavelength at 532 nm is 5.68 x 10{sup -5}, which indicate the good optical homogeneity of this crystal. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. Specific heat and linear birefringence behaviour of 4-aminopyridinium tetrachloroantimonate (III), [4-NH{sub 2}C{sub 5}H{sub 4}NH][SbCl{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Przeslawski, J [Institute of Experimental Physics, University of Wroclaw, Max Born Square 9, 50-204 Wroclaw (Poland); Kosturek, B [Institute of Experimental Physics, University of Wroclaw, Max Born Square 9, 50-204 Wroclaw (Poland); Jakubas, R [Faculty of Chemistry, University of Wroclaw, F Joliot Curie 14, 50-383 Wroclaw (Poland)

    2003-11-05

    Thermal (specific heat) and optical (linear birefringence) studies were performed for a new ferroelectric crystal [4-NH{sub 2}C{sub 5}H{sub 4}NH][SbCl{sub 4}]. Four phase transitions were confirmed and described. Thermal parameters ({delta}H, {delta}S) of the normal-incommensurate, N-IC, and incommensurate-ferroelectric commensurate, IC-F(C), phase transitions are given. The order-disorder mechanism of the N-IC phase transition is proved but the displacive one for the IC-F(C) transition can be proposed. The critical index value (2{beta} = 0.68 {+-} 0.02) estimated from the linear birefringence measurements indicates that the N-IC phase transition can be described in terms of the 3d XY model. (letter to the editor)

  18. On the interpretation of negative birefringence observed in strong-field optical pump-probe experiments: high-order Kerr and plasma grating effects

    CERN Document Server

    Karras, G; Houzet, J; Hertz, E; Billard, F; Lavorel, B; Faucher, O

    2013-01-01

    The analysis of negative birefringence optically induced in major air components (Loriot et al., [1, 2]) is revisited in light of the recently reported plasma grating-induced phase-shift effect predicted for strong field pump-probe experiments (Wahlstrand and Milchberg, [3]). The nonlinear birefrin- gence induced by a short and intense laser pulse in argon is measured by femtosecond time-resolved polarimetry. The experiments are performed with degenerate colors, where the pump and probe beam share the same spectrum, or with two different colors and non-overlapping spectra. The in- terpretation of the experimental results is substantiated using a numerical 3D+1 model accounting for nonlinear propagation effects, cross-beam geometry of the interacting laser pulses, and detec- tion technique. The model also includes the ionization rate of argon and high-order Kerr indices introduced by Loriot et al. enabling to assess the contribution of both terms to the observed effect. The results show that the ionization-ind...

  19. The role of scattering and absorption on the optical properties of birefringent polycrystalline ceramics: Modeling and experiments on ruby (Cr:Al2O3)

    Science.gov (United States)

    Penilla, E. H.; Hardin, C. L.; Kodera, Y.; Basun, S. A.; Evans, D. R.; Garay, J. E.

    2016-01-01

    Light scattering due to birefringence has prevented the use of polycrystalline ceramics with anisotropic optical properties in applications such as laser gain media. However, continued development of processing technology has allowed for very low porosity and fine grains, significantly improving transparency and is paving the way for polycrystalline ceramics to be used in demanding optical applications. We present a method for producing highly transparent Cr3+ doped Al2O3 (ruby) using current activated pressure assisted densification. The one-step doping/densification process produces fine grained ceramics with well integrated (doped) Cr, resulting in good absorption and emission. In order to explain the light transmission properties, we extend the analytical model based on the Rayleigh-Gans-Debye approximation that has been previously used for undoped alumina to include absorption. The model presented captures reflection, scattering, and absorption phenomena in the ceramics. Comparison with measured transmission confirms that the model adequately describes the properties of polycrystalline ruby. In addition the measured emission spectra and emission lifetime are found to be similar to single crystals, confirming the high optical quality of the ceramics.

  20. Observation of a low-symmetry phase in Na0.5Bi0.5TiO3 crystals by optical birefringence microscopy

    International Nuclear Information System (INIS)

    Single crystals of sodium bismuth titanate (Na0.5Bi0.5TiO3, NBT) (pure and Mn-doped) have been investigated by means of optical birefringence microscopy. For both crystals, it was found that, above ∝573 K, the optical axis is perfectly aligned with one of the pseudocubic left angle 001 right angle PC directions, while the domain walls appearing in the images are parallel to the pseudocubic left angle 011 right angle PC directions. These observations are consistent with a tetragonal symmetry. Below ∝573 K, the observed optical orientation of both crystals shows a broad angular distribution, with no clearly visible crystallographically oriented domain walls. These results are consistent with monoclinic symmetry. Most importantly, the direct observation of the temperature-driven rotation of the optical axis within the monoclinic plane is reported for the first time in a perovskite oxide material, in the present case for Mn-doped NBT. This has consequences for the understanding of phase transitions in technologically relevant compounds, such as PbZr1-xTixO3, which are considered to have monoclinic structure in some parts of the phase diagram. (orig.)

  1. POINT-BY-POINT INSCRIPTION OF FIBER BRAGG GRATINGS INTO BIREFRINGENT OPTICAL FIBER THROUGH PROTECTIVE ACRYLATE COATING BY TI:SA FEMTOSECOND LASER

    Directory of Open Access Journals (Sweden)

    S. V. Arkhipov,

    2016-05-01

    Full Text Available The paper deals withpoint-by-point inscriptionof fiber Bragg gratings by the 800 nm Ti:Sa femtosecond laser pulses into a unique birefringent fiber with elliptical stress cladding of home manufacture. The proposed inscriptionmethod has advantages over the conventional phase mask method. The possibility to create complex grating structures and relatively high transparency of acrylate coating to the Ti:Sa femtosecond laser radiation of 800 nm gives the possibility for inscriptionof phase shifting gratings, chirped grating and superstructures without stripping the fiber. Also, this method makes it possible to inscribethese diffractive structures with and without co-doping of GeO2 in the fiber core. Achieved reflectance was 10%. The microscopic image of the diffractive structure in the fiber core is presented. The grating of 1.07 µm is realized by pulling the fiber with constant speed while the laser pulses are applied with a repetition frequency of 1 kHz. The results are usable in the sphere of creation of different fiber optic sensitive elements based on Bragg gratings.

  2. Test of Halperin-Lubensky-Ma crossover function at the N -Sm -A transition in liquid crystal binary mixtures via high-resolution birefringence measurements

    Science.gov (United States)

    Yıldız, Sevtap; ćetinkaya, Mehmet Can; Üstünel, Şenay; Özbek, Haluk; Thoen, Jan

    2016-06-01

    We report optical birefringence data for a series of mixtures of the liquid crystals octylcyanobiphenyl (8CB) and decylcyanobiphenyl (10CB). Nematic order parameter S data in the nematic and smectic A phases have been derived from phase angle changes obtained in temperature scans with a rotating analyzer method. These S values have been used to arrive at values for possible entropy discontinuities at the smectic A to nematic phase transition temperature TN A. The 10CB mole fraction dependence of the obtained entropy discontinuities could be well fitted with a crossover function consistent with the mean-field free-energy expression with a nonzero cubic term arising from the coupling between the smectic-A order parameter and the orientational order parameter director fluctuations in the Halperin-Lubensky-Ma theory. The obtained results are in good agreement with existing results from adiabatic scanning calorimetry. By exploiting the fact that the temperature derivative of the order parameter S (T ) near TN A exhibits the same power law divergence as the specific heat capacity, we have extracted the effective critical exponent α values for the compositions under study. The critical exponent α has been observed to reach the tricritical value αTCP=0.5 for the 10CB mole fraction of x =0.330 .

  3. Superior electro-optical properties of electrically controlled birefringence mode using solution-derived La{sub 2}O{sub 3} films

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae-Chang; Park, Hong-Gyu; Lee, Ju Hwan; Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr [Information Display Device Laboratory, Department of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Oh, Byeong-Yun [ZeSHTech Co., Ltd., Business Incubator, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2015-11-15

    The authors demonstrate a high performance electrically controlled birefringence (ECB) mode with solution-derived La{sub 2}O{sub 3} films at various molar concentrations. Uniform and homogeneous liquid crystal (LC) alignment was spontaneously achieved on the La{sub 2}O{sub 3} films for lanthanum concentrations at ratios greater than and equal to 0.2. A preferred orientation of LC molecules appeared along the filling direction, and the LC alignment was maintained via van der Waals force by nanocrystals of the La{sub 2}O{sub 3} films. The LC alignment mechanism was confirmed by x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. Superior electro-optical characteristics of the ECB cells constructed with solution-derived La{sub 2}O{sub 3} films were observed, which suggests that the proposed solution-derived La{sub 2}O{sub 3} films have strong potential for use in the production of advanced LC displays.

  4. Generation and controlling of the dispersive wave by femtosecond pulses propagating in the normal dispersion regimes of the birefringent photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper studies the generation of the dispersive wave (DW) in the normal dispersion regimes of the birefringent photonic crystal fiber (BPCF) fabricated in this work. The remarkable blue-shifted radiation is found to be generated when 30 fs pulses are input in the normal dispersion regime of the BPCF for the first time. The characteristics of the blue-shifted DW strongly depend on the polarization of the input pulse. As a result, two peaks appear in the blue-shifted region of the spectrum when the input pulses polarize along the slow axis of the BPCF. With the increase of the center wavelength of the initial input pulse, the difference between the wavelengths of the two peaks widens. The peak location in the spectrum can be explained by the phase matching condition between the DW and the input pulse. In addition, when the input polarization is set to an angle of 45° with respect to the principal axes of the BPCF, the cross-phase modulation and coherent coupling between two orthogonally polarized modes would result in pulse trapping in the BPCF. Accordingly, the DW shift toward short wavelength is restrained. The DW generation in the normal-dispersion regimes of BPCF can be controlled by the phase matching condition and polarization of the input pulse.

  5. Realization of a free-space 2 × 4 90° optical hybrid based on the birefringence and electro-optic effects of crystals

    International Nuclear Information System (INIS)

    A free-space 2 × 4 90° optical hybrid with electro-optic modulation is presented. The hybrid principally consists of two pairs of electro-optic crystal plates coated with gold electrodes and a polarization analyzer. The optical hybrid uses the birefringence effect of a crystal to split and combine a signal beam and a local oscillator beam, uses the electro-optic effect to introduce a phase modulation and produce a phase shift, and outputs four-channel signal/local oscillator mixed beams whose phase difference can be adjusted continuously. A LiNbO3 crystal is used to design and manufacture the space optical hybrid, and an experimental system is used to verify its performance. The results show that the output phase of the hybrid is continuously adjustable, enabling the hybrid to function perfectly as a 2 × 4 90° space optical hybrid under an appropriate electric field, and that the phase error can be compensated for by an electric field adjustment. (paper)

  6. Measurement of the magnetically-induced QED birefringence of the vacuum and an improved search for laboratory axions: Technical report. Project definition study of the use of assets and facilities of the Superconducting Super Collider Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.A.; Fairbank, W.M. Jr.; Toki, W.H. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Physics; Hall, J.L. [Univ. of Colorado, Boulder, CO (United States). Joint Inst. for Lab. Astrophysics]|[National Inst. of Standards and Technology, Boulder, CO (United States); Kraushaar, P.F. Jr.; Jaffery, T.S. [Superconducting Super Collider Lab., Waxahachie, TX (United States)

    1994-10-31

    The Colorado State Collaboration has studied the feasibility of a high sensitivity QED birefringence/axion search measurement. The objective of this work is to measure, for the first time, the birefringence induced in the vacuum on a light beam travelling in a powerful magnetic field. The same experimental setup also allows a highly sensitive search for axion or axion-like particles. The experiment would combined custom-designed optical heterodyne interferometry with a string of six SSC prototype superconducting dipole magnets at the N-15 site of the SSC Laboratory. With these powerful laser tools, sensitivity advances of 10{sup 7} to 10{sup 9} over previous optical experiments will be possible. The proposed experiment will be able to measure the QED light-by-light scattering effect with a 0.5% accuracy. The increased sensitivity for the axion-two photon interaction will result in a bound on this process rivaling the results based on astrophysical arguments. In the technical report the authors address the scientific significance of these experiments and examine the limiting technical parameters which control their feasibility. The proposed optical/electronic scheme is presented in the context of a background of the known and projected systematic problems which will confront any serious attempt to make such measurements.

  7. Measurement of the magnetically-induced QED birefringence of the vacuum and an improved search for laboratory axions: Technical report. Project definition study of the use of assets and facilities of the Superconducting Super Collider Laboratory

    International Nuclear Information System (INIS)

    The Colorado State Collaboration has studied the feasibility of a high sensitivity QED birefringence/axion search measurement. The objective of this work is to measure, for the first time, the birefringence induced in the vacuum on a light beam travelling in a powerful magnetic field. The same experimental setup also allows a highly sensitive search for axion or axion-like particles. The experiment would combined custom-designed optical heterodyne interferometry with a string of six SSC prototype superconducting dipole magnets at the N-15 site of the SSC Laboratory. With these powerful laser tools, sensitivity advances of 107 to 109 over previous optical experiments will be possible. The proposed experiment will be able to measure the QED light-by-light scattering effect with a 0.5% accuracy. The increased sensitivity for the axion-two photon interaction will result in a bound on this process rivaling the results based on astrophysical arguments. In the technical report the authors address the scientific significance of these experiments and examine the limiting technical parameters which control their feasibility. The proposed optical/electronic scheme is presented in the context of a background of the known and projected systematic problems which will confront any serious attempt to make such measurements

  8. Changes in cAMP and cGMP concentration birefringent fibrils and contractile activity accompanying UV and blue light photoavoidance in plasmodia of an albino strain of Physarum polycephalum

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Tetsuo; Mori Yoshihito; Nakagaki, Toshiyuki; Kobatake, Yonosuke

    1988-02-01

    Photoavoidance by plasmodia of an albino strain of Physarum polycephalum was studied. When the organism was irradiated locally, the protoplasm moved away from the irradiated region. The action spectrum for this avoidance showed three peaks at about 260, 370 and 460 nm. The organism was about one hundred times as sensitive to far UV as to near UV and blue light, and high intensity far-UV caused the gelation of the protoplasm. Irradiation with UV or blue light increased the mean level or the amplitude of oscillation in intracellular cAMP and cGMP concentrations. Upon UV irradiation, birefringent fibrils, presumably microfilaments of F-actin, became thick and numerous, and the plasmodial strand generated a strong tensile force. It is postulated that UV or blue light brings about an increased concentration of cyclic nucleotides which leads to an enhanced local development of contractile fibrils which squeeze protoplasmic sol from the area, resulting in photoavoidance.

  9. Spatial-frequency Fourier polarimetry of the complex degree of mutual anisotropy of linear and circular birefringence in the diagnostics of oncological changes in morphological structure of biological tissues

    Science.gov (United States)

    Ushenko, Yu A.; Gorskii, M. P.; Dubolazov, A. V.; Motrich, A. V.; Ushenko, V. A.; Sidor, M. I.

    2012-08-01

    Theory of polarisation-correlation analysis of laser images of histological sections of biopsy material from cervix tissue based on spatial frequency selection of linear and circular birefringence mechanisms is formulated. Comparative results of measuring the coordinate distributions of the complex degree of mutual anisotropy (CDMA), produced by fibrillar networks formed by myosin and collagen fibres of cervix tissue in different pathological conditions, namely, pre-cancer (dysplasia) and cancer (adenocarcinoma), are presented. The values and variation ranges of statistical (moments of the first — fourth order), correlation (excess-autocorrelation functions), and fractal (slopes of approximating curves and dispersion of extrema of logarithmic dependences of power spectra) parameters of the CDMA coordinate distributions are studied. Objective criteria for pathology diagnostics and differentiation of its severity degree are determined.

  10. Spatial-frequency Fourier polarimetry of the complex degree of mutual anisotropy of linear and circular birefringence in the diagnostics of oncological changes in morphological structure of biological tissues

    Energy Technology Data Exchange (ETDEWEB)

    Ushenko, Yu A; Gorskii, M P; Dubolazov, A V; Motrich, A V; Ushenko, V A; Sidor, M I [Yuriy Fedkovych Chernivtsi National University, Chernivtsi (Ukraine)

    2012-08-31

    Theory of polarisation-correlation analysis of laser images of histological sections of biopsy material from cervix tissue based on spatial frequency selection of linear and circular birefringence mechanisms is formulated. Comparative results of measuring the coordinate distributions of the complex degree of mutual anisotropy (CDMA), produced by fibrillar networks formed by myosin and collagen fibres of cervix tissue in different pathological conditions, namely, pre-cancer (dysplasia) and cancer (adenocarcinoma), are presented. The values and variation ranges of statistical (moments of the first - fourth order), correlation (excess-autocorrelation functions), and fractal (slopes of approximating curves and dispersion of extrema of logarithmic dependences of power spectra) parameters of the CDMA coordinate distributions are studied. Objective criteria for pathology diagnostics and differentiation of its severity degree are determined. (image processing)

  11. Spatial-frequency Fourier polarimetry of the complex degree of mutual anisotropy of linear and circular birefringence in the diagnostics of oncological changes in morphological structure of biological tissues

    International Nuclear Information System (INIS)

    Theory of polarisation-correlation analysis of laser images of histological sections of biopsy material from cervix tissue based on spatial frequency selection of linear and circular birefringence mechanisms is formulated. Comparative results of measuring the coordinate distributions of the complex degree of mutual anisotropy (CDMA), produced by fibrillar networks formed by myosin and collagen fibres of cervix tissue in different pathological conditions, namely, pre-cancer (dysplasia) and cancer (adenocarcinoma), are presented. The values and variation ranges of statistical (moments of the first — fourth order), correlation (excess-autocorrelation functions), and fractal (slopes of approximating curves and dispersion of extrema of logarithmic dependences of power spectra) parameters of the CDMA coordinate distributions are studied. Objective criteria for pathology diagnostics and differentiation of its severity degree are determined. (image processing)

  12. 磁致双折射和二向色性对磁性液体薄片的光透射率弛豫特性的影响%Effect of magnetic field - induced birefringence and dichroism on relaxation behavior of light transmissivity in ferrofluids film

    Institute of Scientific and Technical Information of China (English)

    陆樟献; 龚雁; 王渊明; 王正才; 陈善飞

    2012-01-01

    The purpose of this paper is to investigate the effect of magnetic field - induced birefringence and dichroism on relaxation behavior of light transmissivity in ferrofluids film in term of the Xu' s oscillating magnetic dipole model and the Matsumoto' s birefringence relaxation theory. The specific expression of polarized light transmissivity about birefringence and dichroism is theoretically deduced and numerically simulated. The study has a certain significance on deeper understanding of the optical anisotropy and related application of ferrofluids.%基于Xu等人的经典振荡磁偶极子模型和Matsumoto等人给出的双折射驰豫理论,研究了磁致双折射和二向色性对磁性液体薄片的光透射率弛豫特性的影响.理论推导了磁性液体的双折射和二向色性函数的偏振光透射率具体表达式,并进行了数值模拟计算.该问题的研究对磁性液体光学各向异性的深入认识以及相关磁性液体光学器件的应用具有一定的指导意义.

  13. Observation of a low-symmetry phase in Na{sub 0.5}Bi{sub 0.5}TiO{sub 3} crystals by optical birefringence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gorfman, S.; Thomas, P.A. [Warwick Univ. (United Kingdom). Dept. of Physics; Glazer, A.M. [Oxford Univ. (United Kingdom). Clarendon Lab.; Noguchi, Y.; Miyayama, M. [Tokyo Univ. (Japan); Luo, H. [Shanghai Institute of Ceramics, Shanghai (China)

    2012-06-15

    Single crystals of sodium bismuth titanate (Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}, NBT) (pure and Mn-doped) have been investigated by means of optical birefringence microscopy. For both crystals, it was found that, above {proportional_to}573 K, the optical axis is perfectly aligned with one of the pseudocubic left angle 001 right angle {sub PC} directions, while the domain walls appearing in the images are parallel to the pseudocubic left angle 011 right angle {sub PC} directions. These observations are consistent with a tetragonal symmetry. Below {proportional_to}573 K, the observed optical orientation of both crystals shows a broad angular distribution, with no clearly visible crystallographically oriented domain walls. These results are consistent with monoclinic symmetry. Most importantly, the direct observation of the temperature-driven rotation of the optical axis within the monoclinic plane is reported for the first time in a perovskite oxide material, in the present case for Mn-doped NBT. This has consequences for the understanding of phase transitions in technologically relevant compounds, such as PbZr{sub 1-x}Ti{sub x}O{sub 3}, which are considered to have monoclinic structure in some parts of the phase diagram. (orig.)

  14. The flow structure in the near field of jets and its effect on cavitation inception, and, Implementation of ferroelectric liquid crystal and birefringent crystal for image shifting in particle image velocimetry

    Science.gov (United States)

    Gopalan, Shridhar

    1999-10-01

    Cavitation experiments performed in the near field of a 50-mm diameter (D) jet at ReD = 5 × 105, showed inception in the form of inclined ``cylindrical'' bubbles at axial distances (x/D) less than 0.55, with indices of 2.5. On tripping the boundary layer, cavitation inception occurred at x/D ~ 2, as distorted ``spherical'' bubbles with inception indices of 1.7. To investigate these substantial differences, the near field of the jet was measured using Particle Image Velocimetry (PIV). Data on the primary flow, the strength distribution of the ``streamwise''vortices and the velocity profiles within the initial boundary layers were obtained. The untripped case showed a direct transition to three-dimensional flow in the near field (x/D essay we discuss the implementation of electro-optical image shifting to resolve directional ambiguity in PIV measurements. The technique uses a ferroelectric liquid crystal (FLC) as an electro-optic half wave plate and a birefringent crystal (calcite) as the shifter. The system can be used with non-polarized light sources and fluorescent particles. The minimum shifting time is approximately 100μs. This compact electrooptical device usually is positioned in front of the camera lens, though it has also been mounted inside the lens body. This device extensively was used to acquire data in the near field of the jet, which is discussed in Chapter 2. Sample vector maps from a turbulent multidirectional flow are also included.

  15. Polarization-insensitive all-optical dual pump-phase transmultiplexing from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK using cross-phase modulation in a passive nonlinear birefringent photonic crystal fiber

    Science.gov (United States)

    Mahmood, Tanvir

    Considering the network size, bit rate, spectral and channel capacity limitations, different modulation formats may be selectively used in future optical networks. Although the traditional metropolitan area networks (MANs) still uses the non-return-to-zero on-off keying (NRZ-OOK) modulation format due to its technical simplicity and therefore low cost, QPSK format is more advantageous in spectrally efficient long-haul fiber optic transmission systems because of its constant power envelope, and robustness to various transmission impairments. Consequently, an important problem may arise, in particular how to route the OOK-data streams from MANs to long-haul backbone networks when the state of polarization (SOP) of the remotely generated OOK is unpredictable. Hence, the focus of this dissertation was to investigate a polarization insensitive (PI) all-optical nonlinear optical signal processing (NOSP) method that can be implemented at the network cross-connect (X-connect) to transfer data from a remotely and a locally generated OOK data simultaneously to more effectual QPSK format for long-haul transmission. By utilizing cross-phase modulation (XPM) and inherent birefringence of the device, the work demonstrated, for the first time, PI all-optical data transfer utilizing dual pump-phase transmultiplexing (DPTM) from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK in a passive nonlinear birefringent photonic crystal fiber (PCF). Polarization insensitivity was achieved by scrambling the SOP of the remotely generated OOK pump and launching the locally generated OOK pump and the probe off-axis. To mitigate polarization induced power fluctuations and detrimental effects due to nearby partially degenerate and non-degenerate four wave mixings, an optimum pump-probe detuning was also utilized. The PI DPTM RZ-QPSK demonstrated a pre-amplified receiver sensitivity penalty < 5.5 dB at 10--9 bit-error-rate (BER), relative to relative to the FPGA-precoded RZ-DQPSK baseline in ASE

  16. Vacuum Birefringence Caused by Arbitrary Spin Particles

    OpenAIRE

    Kruglov, S. I.

    2007-01-01

    We study the propagation of a linearly polarized laser beam in the external transverse magnetic field taking into consideration the vacuum polarization by arbitrary spin particles. Induced ellipticity of the beam are evaluated using the effective Lagrangian. With the help of the PVLAS experimental data, we obtain bounds on masses of charged higher spin particles contributed to ellipticity.

  17. Polarization correlometry of birefringence images of human blood layers

    Science.gov (United States)

    Ushenko, A. G.; Angelsky, P. O.; Karachevtsev, A. O.; Bodnar, G. B.; Koval, G. D.; Prydiy, O. G.; Marchuk, Yu.

    2013-12-01

    To analyze the coordinate-like structure of Stokes-parametric and Mueller-matrix images of optically anisotropic components of biological tissues, the two-point polarization-correlational approach was applied. On this basis parameters the method of cross-correlational definition of parameters (average sizes, asymmetry factor) of correlational contour was developed, which defines the topographical structure of the characteristic meanings of Stokes-parametric and Mueller-matrix images of histological sections of biological tissues.

  18. Rashba Spin Orbit Interaction and Birefringent Electron Optics in Graphene

    OpenAIRE

    Asmar, Mahmoud M.; Ulloa, Sergio E.

    2012-01-01

    Electron optics exploits the analogies between rays in geometrical optics and electron trajectories, leading to interesting insights and potential applications. Graphene, with its two-dimensionality and photon-like behavior of its charge carriers, is the perfect candidate for the exploitation of electron optics. We show that a circular gate-controlled region in the presence of Rashba spin-orbit interaction in graphene may indeed behave as a Veselago electronic lens but with two different indi...

  19. Temperature measurement and stabilization in a birefringent whispering gallery resonator

    OpenAIRE

    Strekalov, D. V.; Thompson, R.J.; Baumgartel, L. M.; Grudinin, I. S.; Yu, N

    2011-01-01

    Temperature measurement with nano-Kelvin resolution is demonstrated at room temperature, based on the thermal dependence of an optical crystal anisotropy in a high quality whispering gallery resonator. As the resonator's TE and TM modes frequencies have different temperature coefficients, their differential shift provides a sensitive measurement of the temperature variation, which is used for active stabilization of the temperature.

  20. Highly birefringent crystal for Raman transitions with phase modulators

    Science.gov (United States)

    Arias, Nieves; Abediyeh, Vahide; Hamzeloui, Saeed; Jeronimo-Moreno, Yasser; Gomez, Eduardo

    2016-05-01

    We present a system to excite Raman transitions with minimum phase noise. The system uses a phase modulator to generate the phase locked beams required for the transition. We use a long calcite crystal to filter out one of the sidebands, avoiding the cancellation that appears at high detunings for phase modulation. The measured phase noise is limited by the quality of the microwave synthesizer. We use the calcite crystal a second time to produce a co-propagating Raman pair with perpendicular polarizations to drive velocity insensitive Raman transitions. Support from CONACYT and Fundacion Marcos Moshinsky.

  1. The Double Jones Birefringence in Magneto-electric Medium

    OpenAIRE

    Waqas Mahmood; Qing Zhao

    2014-01-01

    In this paper, the Maxwell’s equations for a tensorial magneto-electric (ME) medium are solved, which is an extension to the work on the uniaxial anisotropic nonmagnetic medium. The coefficients of the dielectric permittivity, magnetic permeability, and of the magneto-electric effect are considered as tensors. The polarization is shown lying in the plane of two perpendicular independent vectors, and the relationship for the transverse polarization is given. The propagation of an electromagnet...

  2. Birefringence in heat-mechanical modified freshly moulded polyester fibers

    International Nuclear Information System (INIS)

    The article submits new experimental data concerning to the role of combined thermo-mechanical treatments on the structural development of freshly moulded uncrystallized but crystallizable poly (ethylene terephthalate) (PET) fibers. The object of the present work is PET as a thermoplastic polymer with a large practical application. The report is devoted to the influence of the heat-mechanical modification temperature on the structure rearrangement in uniaxially orientated amorphous PET. The heat-mechanical modification of the investigated yarns and the optical measurements were realized by specialized gears constructed and built in the author's laboratories. The fibers heat-mechanical modification includes samples annealing at constant temperature above their glass transition temperature (Tg) without strain stress. The yarn annealing has been followed from well defined uniaxially strain-loading with values from 0 MPa up to 30 MPa during two minutes. The optical measurements were carried out by an optical system using a polarization microscope and a CCD camera. The obtained experimental data has been analyzed by Mocha-1.2 (Jandel Scientific) software. There are established dependences between the heat-mechanical modification mode and the structural rearrangements running in the studied PET samples.

  3. Ultrafast acousto-optic mode conversion in optically birefringent ferroelectrics.

    Science.gov (United States)

    Lejman, Mariusz; Vaudel, Gwenaelle; Infante, Ingrid C; Chaban, Ievgeniia; Pezeril, Thomas; Edely, Mathieu; Nataf, Guillaume F; Guennou, Mael; Kreisel, Jens; Gusev, Vitalyi E; Dkhil, Brahim; Ruello, Pascal

    2016-01-01

    The ability to generate efficient giga-terahertz coherent acoustic phonons with femtosecond laser makes acousto-optics a promising candidate for ultrafast light processing, which faces electronic device limits intrinsic to complementary metal oxide semiconductor technology. Modern acousto-optic devices, including optical mode conversion process between ordinary and extraordinary light waves (and vice versa), remain limited to the megahertz range. Here, using coherent acoustic waves generated at tens of gigahertz frequency by a femtosecond laser pulse, we reveal the mode conversion process and show its efficiency in ferroelectric materials such as BiFeO3 and LiNbO3. Further to the experimental evidence, we provide a complete theoretical support to this all-optical ultrafast mechanism mediated by acousto-optic interaction. By allowing the manipulation of light polarization with gigahertz coherent acoustic phonons, our results provide a novel route for the development of next-generation photonic-based devices and highlight new capabilities in using ferroelectrics in modern photonics. PMID:27492493

  4. Lorentz-violation-induced vacuum birefringence and its astrophysical consequences

    Science.gov (United States)

    Shao, Lijing; Ma, Bo-Qiang

    2011-06-01

    In the electromagnetism of loop quantum gravity, two helicities of a photon have different phase velocities and group velocities, termed as “vacuum birefringence”. Two novel phenomenons, “peak doubling” and “depolarization”, are expected to appear for a linearly polarized light from astrophysical sources. We show that the criteria to observe these two phenomenons are the same. Further, from recently observed γ-ray polarization from Cygnus X-1, we obtain an upper limit ˜8.7×10-12 for the Lorentz-violating parameter χ, which is the most firm constraint from well-known systems. We also suggest analyzing the possible existence of “peak doubling” through Fermi-LAT gamma-ray bursts.

  5. Equivalence principle and electromagnetic field: no birefringence, no dilaton, and no axion

    CERN Document Server

    Hehl, Friedrich W

    2007-01-01

    The coupling of the electromagnetic field to gravity is discussed. In the premetric axiomatic approach based on the experimentally well established conservation laws of electric charge and magnetic flux, the Maxwell equations are the same irrespective of the presence or absence of gravity. In this sense, one can say that the charge "substratum" and the flux "substratum" are not influenced by the gravitational field directly. However, the interrelation between these fundamental substrata, formalized as the {\\it spacetime relation} H=H(F) between the 2-forms of the electromagnetic excitation H and the electromagnetic field strength F, is affected by gravity. Thus the validity of the equivalence principle for electromagnetism depends on the form of the spacetime relation. We discuss the nonlocal and local linear constitutive relations and demonstrate that the spacetime metric can be accompanied also by skewon, dilaton, and axion fields. All these premetric companions of the metric may eventually lead to a violat...

  6. Frequency-domain birefringence measurement of biological binding to magnetic nanoparticles.

    Science.gov (United States)

    Ku, Benjamin Y; Chan, Mei-Lin; Ma, Zhiya; Horsley, David A

    2008-01-01

    Optical detection of the frequency-dependent magnetic relaxation signal is used to monitor the binding of biological molecules to magnetic nanoparticles in a ferrofluid. Biological binding reactions cause changes in the magnetic relaxation signal due to an increase in the average hydrodynamic diameter of the nanoparticles. To allow the relaxation signal to be detected in dilute ferrofluids, measurements are made using a balanced photodetector, resulting in a 25 μV/√Hz noise floor, within 50% of the theoretical limit imposed by photon shot noise. Measurements of a ferrofluid composed of magnetite nanoparticles coated with anti-IgG antibodies show that the average hydrodynamic diameter increases from 115.2 to 125.4 nm after reaction with IgG. PMID:20463913

  7. Frequency-domain birefringence measurement of biological binding to magnetic nanoparticles

    OpenAIRE

    Ku, Benjamin Y.; Chan, Mei-Lin; Ma, Zhiya; Horsley, David A.

    2008-01-01

    Optical detection of the frequency-dependent magnetic relaxation signal is used to monitor the binding of biological molecules to magnetic nanoparticles in a ferrofluid. Biological binding reactions cause changes in the magnetic relaxation signal due to an increase in the average hydrodynamic diameter of the nanoparticles. To allow the relaxation signal to be detected in dilute ferrofluids, measurements are made using a balanced photodetector, resulting in a 25 μV/√Hz noise floor, within 50% ...

  8. Frequency-domain birefringence measurement of biological binding to magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ku, Benjamin Y.; Chan, M.-L.; Ma Zhiya [Department of Mechanical and Aeronautical Engineering, University of California, Bainer Hall, 1 Shields Ave., Davis, CA 95616 (United States); Horsley, David A. [Department of Mechanical and Aeronautical Engineering, University of California, Bainer Hall, 1 Shields Ave., Davis, CA 95616 (United States)], E-mail: dahorsley@ucdavis.edu

    2008-09-15

    Optical detection of the frequency-dependent magnetic relaxation signal is used to monitor the binding of biological molecules to magnetic nanoparticles in a ferrofluid. Biological binding reactions cause changes in the magnetic relaxation signal due to an increase in the average hydrodynamic diameter of the nanoparticles. To allow the relaxation signal to be detected in dilute ferrofluids, measurements are made using a balanced photodetector, resulting in a 25 {mu}V/{radical}Hz noise floor, within 50% of the theoretical limit imposed by photon shot noise. Measurements of a ferrofluid composed of magnetite nanoparticles coated with anti-IgG antibodies show that the average hydrodynamic diameter increases from 115.2 to 125.4 nm after reaction with IgG.

  9. Stress-induced birefringence in elastomers doped with ferrofluid magnetic particles: Mechanical and optical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Sena, C. [Instituto de Fisica, Universidade de Sao Paulo, Caixa postal 66318, Sao Paulo, SP 05315-970 (Brazil); Bailey, C. [Liquid Crystal Institute, Kent State University, P.O. Box 5190, Kent, OH 44242-0001 (United States); Godinho, M.H. [Faculdade de Ciencias e Tecnologia e CENIMAT, Universidade Nova de Lisboa, Quinta da Torre, P-2829-516 Caparica (Portugal); Figueirinhas, J.L. [CFMC, Universidade de Lisboa, Avenida Prof. Gama Pinto 2, 1649 003 Lisbon (Portugal); Palffy-Muhoray, P. [Liquid Crystal Institute, Kent State University, P.O. Box 5190, Kent, OH 44242-0001 (United States); Figueiredo Neto, A.M. [Instituto de Fisica, Universidade de Sao Paulo, Caixa postal 66318, Sao Paulo, SP 05315-970 (Brazil)]. E-mail: afigueiredo@if.usp.br

    2006-05-15

    Magnetic nanoparticles from magnetic colloidal suspensions were incorporated in the urethane/urea elastomer (PU/PBDO) by adding to the prepolymers solution in toluene diverse amounts of magnetite grains. It is shown that ferrofluid grains can be efficiently incorporated into the elastomer according to this procedure. Mechanical and optical experiments performed show that the elastomer preparation procedure (casting) introduces a structural anisotropy on the optically isotropic sample. This fact is put in evidence by the measurements of the Young's moduli and orientation of the sample's optical axis under stress. The dependence of the phase shift of both the pure and ferrofluid-doped elastomer samples under strain is linear, and the strain-optic coefficient is show to be linear with the ferrofluid concentration.

  10. Characterization of Birefringence and Dispersion Properties in an Arrayed Waveguide Grating

    Institute of Scientific and Technical Information of China (English)

    Jeong Hwan Song; Oh Dal Kwon; Dong-Su Kim; Sun Tae Jung; Kyung Shik Lee

    2003-01-01

    We have characterized polarization dependent loss(PDL), differential group delay(DGD), and chromatic dispersion of an AWG and a simple method was proposed to estimate the chromatic dispersion from the measured DGD of the device.

  11. Low birefringent magneto-optical waveguides fabricated via organic-inorganic sol-gel process

    OpenAIRE

    Choueikani, F.; ROYER,F; Douadi, S.; Skora, A.; Jamon, D.; Blanc, D.; Siblini, A.

    2009-01-01

    Abstract This paper is devoted to the study and the characterization of novel magneto-optical waveguides prepared via organic-inorganic sol-gel process. Thin silica/zirconia films doped with magnetic nanoparticles were coated on glass substrate using dip-coating technique. After annealing, samples were UV-treated. Two different techniques were used to measure their properties: m-lines spectroscopy and free space ellipsometry. Results evidence low refractive index waveguides that co...

  12. Stress-induced birefringence in elastomers doped with ferrofluid magnetic particles: Mechanical and optical investigation

    International Nuclear Information System (INIS)

    Magnetic nanoparticles from magnetic colloidal suspensions were incorporated in the urethane/urea elastomer (PU/PBDO) by adding to the prepolymers solution in toluene diverse amounts of magnetite grains. It is shown that ferrofluid grains can be efficiently incorporated into the elastomer according to this procedure. Mechanical and optical experiments performed show that the elastomer preparation procedure (casting) introduces a structural anisotropy on the optically isotropic sample. This fact is put in evidence by the measurements of the Young's moduli and orientation of the sample's optical axis under stress. The dependence of the phase shift of both the pure and ferrofluid-doped elastomer samples under strain is linear, and the strain-optic coefficient is show to be linear with the ferrofluid concentration

  13. Optical fiber Sagnac interferometer for sensing scalar directional refraction: application to magnetochiral birefringence

    CERN Document Server

    Loas, Goulc'hen; Vallet, Marc

    2014-01-01

    We present a set-up dedicated to the measurement of the small scalar directional anisotropies associated to the magnetochiral interaction. The apparatus, based on a polarization-independent fiber Sagnac interferometer, is optimized to be insensitive to circular anisotropies and to residual absorption. It can thus characterize samples of biological interests, for which the two enantiomers are not available and/or which present poor transmission. The signal-to-noise ratio is shown to be limited only by the source intensity noise, leading to a detection limit of Df = 500 nrad.Hz-1/2. It yields a limit on the magnetochiral index nMC < 4 10-13 T-1 at 1550 nm for the organic molecules tested.

  14. Direct writing of birefringent elements by ultrafast laser nanostructuring in multicomponent glass

    Science.gov (United States)

    Fedotov, S. S.; Drevinskas, R.; Lotarev, S. V.; Lipatiev, A. S.; Beresna, M.; ČerkauskaitÄ--, A.; Sigaev, V. N.; Kazansky, P. G.

    2016-02-01

    Self-assembled nanostructures created by femtosecond laser irradiation are demonstrated in alkali-free aluminoborosilicate glass. The growth of the induced retardance associated with the nanograting formation is three orders of magnitude slower than in silica glass and is observed only within a narrow range of pulse energies. However, the strength of retardance asymptotically approaches the value typically measured in pure silica glass, which is attractive for practical applications. A similar intensity threshold for nanograting formation of about 1 TW/cm2 is observed for all glasses studied. The radially polarized vortex beam micro-converter designed as a space-variant quarter-wave retarder for the near-infrared spectral range is imprinted in commercial Schott AF32 glass.

  15. Systematic study of magnetic linear dichroism and birefringence in (Ga,Mn)As

    Czech Academy of Sciences Publication Activity Database

    Tesařová, N.; Ostatnický, T.; Novák, Vít; Olejník, Kamil; Šubrt, J.; Reichlová, Helena; Ellis, C.T.; Mukherjee, A.; Lee, J.; Sipahi, G.M.; Sinova, Jairo; Hamrle, J.; Jungwirth, Tomáš; Němec, P.; Cerne, J.; Výborný, Karel

    2014-01-01

    Roč. 89, č. 8 (2014), , "085203-1"-"085203-14". ISSN 1098-0121 R&D Projects: GA MŠk(CZ) LM2011026 EU Projects: European Commission(XE) 268066 - 0MSPIN Grant ostatní: AVČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : ferromagnetic semiconductors * magneto -optics Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.736, year: 2014

  16. Giant birefringence silicon nanophotonic multi-slot waveguides for optical delay line applications

    OpenAIRE

    Yang, Shun-Hui

    2008-01-01

    With the vast increase in the amount of data transfer around the world each day, there has been a necessity for rapid development in optical communication and signal processing technologies. Using an all optical scheme to replace the current electronic format shows promise in the next generation of signal processing. In an optical processing system, the optical delay line buffer is a critical component. While significant research has been done on novel delay line schemes, it will be necessary...

  17. Femtosecond transient dichroism/birefringence studies of solute- solvent friction and solvent dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.J.; Castner, E.W. Jr. [Brookhaven National Lab., Upton, NY (United States); Konitsky, W.; Waldeck, D.H. [Pittsburgh Univ., PA (United States). Dept. of Chemistry

    1994-02-01

    Ultrafast, heterodyne, polarization spectroscopies are used to measure solute-solvent frictional coupling and characterize the neat solvent`s relaxation dynamics on femtosecond and picosecond timescales.

  18. Soliton propagation and polarisation mode-locking in birefringent optical fibres

    OpenAIRE

    Afanasjev, V.V.; Grudinin, A. B.

    1993-01-01

    Soliton propagation in polarization-preserving fibres is analysed. Based on the coupled nonlinear Schrodinger equations we derive an analytical approximation for such type of soliton propagation. Exploitation of soliton polarization properties for passive mode-locking in fibre lasers is also considered.

  19. Optical fiber Sagnac interferometer for sensing scalar directional refraction: Application to magnetochiral birefringence

    OpenAIRE

    Loas, Goulc'Hen; Alouini, Mehdi; Vallet, Marc

    2014-01-01

    International audience We present a setup dedicated to the measurement of the small scalar directional anisotropies associated to the magnetochiral interaction. The apparatus, based on a polarization-independent fiber Sagnac interferometer, is optimized to be insensitive to circular anisotropies and to residual absorption. It can thus characterize samples of biological interests, for which the two enantiomers are not available and/or which present poor transmission. The signal-to-noise rat...

  20. Compact Birefringent Waveplates Photo-Induced in Silica by Femtosecond Laser

    OpenAIRE

    Matthieu Lancry; Rudy Desmarchelier; Kevin Cook; Bertrand Poumellec; John Canning

    2014-01-01

    Recently, we showed that femtosecond laser induced “nanogratings” consist of thin regions with a low refractive index (Δn = −0.15), due to the formation of nanoporous silica surrounded by regions with a positive index change. In this paper, we investigate a wide range of laser parameters to achieve very high retardance within a single layer; as much as 350 nm at λ = 546 nm but also to minimize the competing losses. We show that the total retardance depends on the number of layers present and ...

  1. Analytical Approach to Polarization Mode Dispersion in Linearly Spun Fiber with Birefringence

    Directory of Open Access Journals (Sweden)

    Vinod K. Mishra

    2016-01-01

    Full Text Available The behavior of Polarization Mode Dispersion (PMD in spun optical fiber is a topic of great interest in optical networking. Earlier work in this area has focused more on approximate or numerical solutions. In this paper we present analytical results for PMD in spun fibers with triangular spin profile function. It is found that in some parameter ranges the analytical results differ from the approximations.

  2. Nonlinear birefringence in plasmas: Polarization dynamics, vector modulational instability, and vector solitons

    Energy Technology Data Exchange (ETDEWEB)

    Borhanian, Jafar, E-mail: borhanian@uma.ac.ir [Department of Physics, Faculty of Science, University of Mohaghegh Ardabili, P. O. Box 179, Ardabil (Iran, Islamic Republic of)

    2014-06-15

    The propagation of an elliptically polarized intense laser pulse in an unmagnetized collisionless uniform plasma is considered. A multiple scale perturbation theory is employed to show that in a weakly relativistic regime, evolution of the components of vector potential is governed by two coherently coupled nonlinear Schrödinger (NLS) equations. A set of equations describing the evolution of Stokes parameters is derived within the continuous wave approximation and the dynamics of components of field amplitude is studied. The polarization dynamics of a pulse is investigated by means of numerical solution of the coupled NLS equations. A detailed analysis of vector modulational instability is presented and the possibility for occurrence of various kinds of vector solitary waves is addressed.

  3. Birefringence and band structure of CdP{sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Beril, S.I.; Stamov, I.G. [Tiraspol State Corporative University, Yablocikin Street 5, 2069 Tiraspol, Republic of Moldova (Moldova, Republic of); Syrbu, N.N., E-mail: sirbunn@yahoo.com [Technical University of Moldova, 168 Stefan cel Mare Avenue, 2004 Chisinau, Republic of Moldova (Moldova, Republic of); Zalamai, V.V. [Institute of Applied Physics, Academy of Sciences of Moldova, 5 Academy Street, 2028 Chisinau, Republic of Moldova (Moldova, Republic of)

    2013-08-01

    The spatial dispersion in CdP{sub 2} crystals was investigated. The dispersion is positive (n{sup k||c}>n{sup k||y}) at λ>λ{sub 0} and negative (n{sup k||c}

  4. Effects of the induced birefringence in photorefractive crystals on speckle optical vortices

    Science.gov (United States)

    Gómez, Jorge A.; Rueda, Edgar; Salazar, Ángel; Tebaldi, Myriam; Bolognini, Nestor; Lencina, Alberto

    2012-03-01

    In this work, we show that it is possible to change the properties of an optical vortex formed in a speckle pattern by the control of an external electric field applied to a sillenite-type photorefractive material in a non-holographic configuration. To show it, a scheme that allows the recovering of both, the polarization state and the phase distribution of an optical field was implemented. Changes in the polarization state of the light in the neighborhood of the vortex were observed with the application of an external electric field. Likewise, changes in the phase structure around the vortex and displacements of the vortices themselves were measured. These displacements have a fairly linear dependence on the applied field to the photorefractive crystal. Experimental results are qualitatively explained with the theoretical treatment of non-holographic recording in photorefractive crystals.

  5. Cross-phase modulational instability in an elliptical birefringent fiber with higher order nonlinearity and dispersion

    Indian Academy of Sciences (India)

    R Ganapathy; V C Kuriakose

    2002-04-01

    We obtain conditions for the occurrence of cross-phase modulational instability in the normal dispersion regime for the coupled higher order nonlinear Schrödinger equation with higher order dispersion and nonlinear terms.

  6. Optimization of reconstruction algorithm for cross-phase modulation frequency-resolve optical gating in a high birefringence microstructured fiber

    Czech Academy of Sciences Publication Activity Database

    Vraný, Boleslav; Honzátko, Pavel; Kaňka, Jiří

    Bellingham : SPIE The International Society for Optical Engineering, 2006 - (Tománek, P.; Hrabovský, M.; Miler, M.; Senderáková, D.), pp.618012.1-618012.6 ISBN 0-8194-6236-5. ISSN 0277-786X. - (Proceedings of SPIE. 6180). [Photonics Prague 2005. International Conference on Photonics, Devices and Systems /5./. Prague (CZ), 08.06.2005-11.06.2005] R&D Projects: GA ČR(CZ) GA102/05/0995 Institutional research plan: CEZ:AV0Z2067918 Keywords : laser variables measurement * genetic algorithms * phase measurement Subject RIV: BH - Optics, Masers, Lasers

  7. Optimization of reconstruction algorithm for cross-phase modulation frequency-resolve optical gating in a high birefringence microstructured fiber

    Czech Academy of Sciences Publication Activity Database

    Vraný, Boleslav; Honzátko, Pavel; Kaňka, Jiří

    Praha : Agentura Action M, 2005. s. 137. ISBN 80-86742-08-3. [Photonics Prague 2005. International Conference on Photonics, Devices and Systems /5./. 08.06.2005-11.06.2005, Prague] R&D Projects: GA ČR(CZ) GA102/05/0995 Institutional research plan: CEZ:AV0Z20670512 Keywords : laser variables measurement * genetic algorithms * phase measurement Subject RIV: BH - Optics, Masers, Lasers

  8. Optimization of reconstruction algorithm for cross-phase modulation frequency-resolve optical gating in a high birefringence microstructured fiber

    Czech Academy of Sciences Publication Activity Database

    Vraný, Boleslav; Honzátko, Pavel; Kaňka, Jiří

    Pilsen : University of West Bohemia, 2005 - (Pinker, J.), s. 357-360 ISBN 80-7043-369-8. [Applied Electronics 2005 [0054019] [0054053]. Pilsen (CZ), 07.09.2005-08.09.2005] R&D Projects: GA ČR(CZ) GA102/05/0995 Institutional research plan: CEZ:AV0Z20670512 Keywords : laser variables measurement * genetic algorithms * phase measurement Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  9. Photodetectors and birefringence in ZnP{sub 2}–S{sub 2h}{sup 5} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Stamov, I.G. [Tiraspol State Corporative University, Yablocicin Street 5, 2069 Tiraspol, Republic of Moldova (Moldova, Republic of); Syrbu, N.N., E-mail: sirbunn@yahoo.com [Technical University of Moldova, 168 Stefan cel Mare Avenue, 2004 Chisinau, Republic of Moldova (Moldova, Republic of); Dorogan, A.V. [Technical University of Moldova, 168 Stefan cel Mare Avenue, 2004 Chisinau, Republic of Moldova (Moldova, Republic of)

    2013-03-01

    The spectral dependences of refractive indexes n{sub o}(n{sup ⊥}), n{sub e}(n{sup ||}) and Δn=n{sub o}(n{sup ⊥})−n{sub e}(n{sup ||}) were studied in ZnP{sub 2}–C{sub 2h}{sup 5} crystals. The intersection of n{sub o}(n{sup ⊥}) and n{sub e}(n{sup ||}) was found for λ{sub 0}=0.906 μm. The crystal possesses positive dispersion Δn=n{sub o}(n{sup ⊥})−n{sub e}(n{sup ||}) in the region where λ>λ{sub 0}, and a negative dispersion is observed in the region where λ<λ{sub 0}. The electrical, spectral and azimuth characteristics of monolith n–r- and Me-n–r-ZnP{sub 2}C{sub 2h}{sup 5} and discrete ZnP{sub 2}–C{sub 2h}{sup 5–}ZnP{sub 2}–D{sub 4}{sup 8} structures were studied, and a prognosis was made on the usage perspective of these devices.

  10. Building a 3.5 m prototype interferometer for the Q & A vacuum birefringence experiment and high precision ellipsometry

    CERN Document Server

    Wu, J S; Chen, S J; Wu, Jeah-Sheng; Ni, Wei-Tou; Chen, Sheng-Jui

    2004-01-01

    We have built and tested a 3.5 m high-finesse Fabry-Perot prototype inteferometer with a precision ellipsometer for the QED test and axion search (Q & A) experiment. We use X-pendulum-double-pendulum suspension designs and automatic control schemes developed by the gravitational-wave detection community. Verdet constant and Cotton-Mouton constant of the air are measured as a test. Double modulation with polarization modulation 100 Hz and magnetic-field modulation 0.05 Hz gives 10^{-7} rad phase noise for a 44-minute integration.

  11. Investigation on crystalline perfection, optical transmittance, birefringence, temperature-dependent refractive index, laser damage threshold and pyroelectric characteristics of inversely soluble lithium sulfate monohydrate single crystals

    Science.gov (United States)

    Silambarasan, A.; Rajesh, P.; Bhatt, Rajeev; Bhaumik, Indranil; Karnal, A. K.; Ramasamy, P.; Gupta, P. K.

    2016-08-01

    Bulk prismatic lithium sulfate monohydrate (LSMH) single crystals were grown by seed rotation with slow heating method from aqueous solution. Small FWHM obtained from high-resolution X-ray diffraction spectrum shows that the crystals grown by this method have less defects and absence of low-angle grain boundaries. The high transmittance and low reflectance nature of the grown crystal was observed using UV-Vis-NIR spectrometer. The principal refractive indices of a LSMH crystal have been measured by a prism coupling method for the wavelengths of 0.407, 0.532, 0.828, 1.064 and 1.551 µm at room temperature, and Sellmeier equations are determined from the fitting of the data point. The refractive index data confirm that LSMH crystal is negative biaxial and the optic axis lies in YZ plane with an angle (2 V y ) of 51.74° with respect to y axis at 532 nm wavelength. The thermo-optic coefficients were determined from the temperature-dependent refractive indices measured in the range of 30-125 °C for the wavelengths of 532 and 1064 nm. The surface laser damage threshold studies reveal the higher optical radiation stability against 532-nm laser. The pyroelectric coefficients and pyroelectric figure of merit were determined from the pyroelectric current measurement by the Byer and Roundy method.

  12. Electric field-induced stress—birefringence in layered composites PbZr1−xTixO3/Polycarbonate

    International Nuclear Information System (INIS)

    Electro—optical composites based on the product of electro—strictive and elasto—optical effects are developed. Layered composites of PbZr1−xTixO3 and polycarbonate are synthesised. Their electro—optical properties are studied. The nominal transverse electro—optical coefficient of the composite is observed to be about 3.6 times larger than that of LiNbO3. Experiments and theoretical analyses show that the electro—optical effect of the composite has a strong ‘size effect’. With the ratio of thickness/length decreasing or the width of elasto—optical phase increasing, the half-wave electric field intensity increases but the transverse electro—optical coefficient decreases for the layered composite. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Linear to radial/azimuthal polarization converter in transmission using form birefringence in a segmented silicon grating manufactured by high productivity microelectronic technologies

    OpenAIRE

    Kampfe, Thomas; Sixt, Pierre; Renaud, Denis; Lagrange, Armelle; Perrin, Fabrice; Parriaux, Olivier

    2014-01-01

    International audience A polarization rotation is realized by subwavelength binary gratings, where the TE and TM round trip phases of the smallest grating modes are fixed to the smallest possible integer numbers of 2pi that allow a straight-through phase difference of pi This results in a subwavelength grating allowing to realize a half-wave element of almost 100% transmission. The principle is applied to a polarization transformation in the 1030-1064 nm wavelength range, using a segmented...

  14. Complete polarization state generator with one variable retarder and its application for fast and sensitive measuring of two-dimensional birefringence distribution

    OpenAIRE

    Shribak, Michael

    2011-01-01

    The complete polarization state generator, which consists of one rotatable polarizer and one variable retarder with quarter-wave plate, is introduced. The orientation angle of its output polarization ellipse equals to half retardance of the variable retarder, and the ellipticity angle corresponds to the polarizer azimuth. The PSG is employed in the quantitative orientation-independent differential polarization microscope, which uses polarized light states with the same ellipticity and differe...

  15. Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser

    International Nuclear Information System (INIS)

    Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N2 on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm2, to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

  16. New photosensitive polymer composites based on oriented porous polyethylene filled with azobenzene-containing LC mixture: reversible photomodulation of dichroism and birefringence

    Czech Academy of Sciences Publication Activity Database

    Bobrovsky, A.; Shibaev, V.; Elyashevitch, G.; Rosova, E.; Shimkin, A.; Shirinyan, V.; Bubnov, Alexej; Kašpar, Miroslav; Hamplová, Věra; Glogarová, Milada

    2008-01-01

    Roč. 35, č. 5 (2008), s. 533-539. ISSN 0267-8292 R&D Projects: GA MŠk OC 175 Institutional research plan: CEZ:AV0Z10100520 Keywords : liquid crystals * photosensitive materials * polyethylen porous film * AZO compounds Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.132, year: 2008

  17. Building a 3.5 m prototype interferometer for the Q and A vacuum birefringence experiment and high-precision ellipsometry

    International Nuclear Information System (INIS)

    We have built and tested a 3.5 m high-finesse Fabry-Perot prototype interferometer with a precision ellipsometer for the QED test and axion search (Q and A) experiment. We use X-pendulum-double-pendulum suspension designs and automatic control schemes developed by the gravitational-wave detection community. The Verdet constant and Cotton-Mouton constant of the air are measured as a test. Double modulation with polarization modulation 100 Hz and magnetic-field modulation 0.05 Hz gives 10-7 rad phase noise for a 44 min integration

  18. Versatile transmission ellipsometry to study linear ferrofluid magneto-optics

    NARCIS (Netherlands)

    Kooij, E.S.; Galca, Aurelian C.; Poelsema, B.

    2006-01-01

    Linear birefringence and dichroism of magnetite ferrofluids are studied simultaneously using spectroscopic ellipsometry in transmission mode. It is shown that this versatile technique enables highly accurate characterisation of magneto-optical phenomena. Magnetic field-dependent linear birefringence

  19. On pulse broadening for optical solitons

    CERN Document Server

    Dorren, H J S

    1999-01-01

    Pulse broadening for optical solitons due to birefringence is investigated. It is shown that in optical fibers with birefringence no pure solitons exist. We present analytical expressions for special solitonic solutions in birefringent optical fibers consisting of a combination of pure solitons propagating along the principal birefringence axis with a different velocity and interaction terms between the solitons. An estimation for the stability of the derived solutions and random polarization mode dispersion is given.

  20. 瞬变电场双折射及其在大分子与胶体溶液中的应用%Transient Electric Birefringence and Its Applications to Polymer Solutions and Colloidal Disper-sions

    Institute of Scientific and Technical Information of China (English)

    许人良; 朱鹏年

    1988-01-01

    @@一、引言 现代电光学重要分支之一的瞬变电场双折射(Transient Electric Birefriengence,简称TEB)是在五十年代初被提出来的。TEB的方法原理是:当溶液中光学各向异性粒子在瞬变电场作用下发生定向排列,或是因去掉瞬变电场后粒子转为无序化排列时,利用溶液产生的双折射信号及其相应变化来探测物质的静态与动态特性;其主要测定参量为粒子的转动扩散系数及偶极矩。近年来随着高速瞬态记录仪与微型处理机的问世与普及,TEB逐渐被广泛应用于生物大分子与合成大分子的结构与构象研究。在胶体化学中,可以用TEB来研究微胶的生长过程,凝胶的凝固过程,以及胶体稳定性等问题[1-5]。TEB已成为测定各向异性介质的电学,光学及水化动力学性质及分子量分布的一种有效手段。

  1. Anisotropy-induced Fano resonance

    OpenAIRE

    Qiu, Cheng-Wei; Novitsky, Andrey; Gao, Lei; Dong, Jian-Wen; Luk'yanchuk, Boris

    2012-01-01

    An optical Fano resonance, which is caused by birefringence control rather than frequency selection, is discovered. Such birefringence-induced Fano resonance comes with fast-switching radiation. The resonance condition $\\varepsilon_t< 1/\\varepsilon_r$ is revealed and a tiny perturbation in birefringence is found to result in a giant switch in the principal light pole induced near surface plasmon resonance. The loss and size effects upon the Fano resonance have been studied Fano resonance is s...

  2. Micromachining with femtosecond laser written radial polarization converter

    OpenAIRE

    Beresna, M.; Gecevičius, M.; Kazansky, P. G.; Bellouard, Y.; Champion, A.

    2012-01-01

    Structures for microfluidics are fabricated with radially polarized femtosecond laser beam. Radial polarization is produced using birefringent optical element. Omnidirectional etching can be achieved using cylindrically symmetric polarization.

  3. A sensitive method of determining optic axis azimuth based on laser feedback

    International Nuclear Information System (INIS)

    A sensitive method to determine the optic axis azimuth of the birefringence element is presented, which is based on laser feedback. The phase difference between the two intensities in birefringence feedback changes with the angle between the optic axis of the birefringence element and laser original polarization. The phase difference is highly sensitive to the relative position of the optic axis and the laser original polarization. This method is used to highly precisely determine the optic axis azimuth, and is able to distinguish between the fast axis and the slow axis of the birefringence element. Theoretical analysis and experimental results are both demonstrated. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  4. Twisted Hi-Bi fiber DFB lasers with controllable output polarization

    OpenAIRE

    M. N. Zervas; Wilmshurst, R.; Walker, L.M.B.

    2012-01-01

    We demonstrate that single polarization, hi-bi fiber DFB lasers are in general characterized by elliptical state of polarization, due to the in-built fiber birefringence axis rotation. Externally applied birefringence-axis twist is shown to provide accurate control of the output SOP. Continuous tuning from circular to linear polarization, with PER of ~40dB has been demonstrated.

  5. Orthogonally linear polarized lasers(Ⅰ)--principle and devices

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shulian; XU Ting

    2005-01-01

    Two kinds of orthogonally polarized lasers, i.e. Zeeman dual-frequency lasers and four-frequency ring lasers (laser gyros) have been developed since the invention of lasers, in which circularly polarized lights oscillate. This paper summarizes recent progress of the study on orthogonally linear polarized lasers with the standing wave cavity. Firstly, the expression of producing orthogonally linear polarized lights in standing wave cavity, i.e. laser frequency splitting, is given. Almost all the birefringence effects made in laser cavity are used to produce orthogonally linear polarized lights. The effect includes quartz crystal birefringence effect, calcite birefringence effect,stress (photo-elastic) birefringence effect and electro-optical birefringence effect. Secondly, several physical phenomena of orthogonally linear polarized lasers are discovered such as aberrance of frequency splitting curves caused by optical activity of quartz crystal, order-passing of longitudinal modes with frequency splitting and strong modes competition. Finally, because the traditional Zeeman dual frequency laser cannot output frequency difference larger than 3 MHz, the approaches of obtaining larger frequency difference are studied. The sequential results, several kinds of orthogonally polarized lasers, are described, such as birefringence dual frequency lasers outputting a frequency difference from 40 MHz to hundreds of megahertz, birefringence-Zeeman dual frequency lasers outputting a frequency difference from 1 MHz to hundreds of megahertz, the LD pumped YAG birefringence dual frequency laser outputting frequency difference of several gigahertz, and the lasers whose longitudinal mode spacing is c/4L instead of c/2L.

  6. Miniature multi-turn fibre current sensors

    OpenAIRE

    Li, L.; Qian, J.R.; Payne, D. N.

    1987-01-01

    Highly birefringent Bow-Tie fibres can be sensitized to Faraday rotation by spinning the fibres during draw. The fibres become elliptically-birefringent and this permits multi-turn small-diameter coil to be wound without loss of current sensitivity.

  7. Proposal to develop techniques using magneto-optic and electro-optic effects in optical fiber for CTR diagnostics

    International Nuclear Information System (INIS)

    We discuss the developing technology of measuring electric and magnetic fields with optical fibers using the Faraday and Kerr effects, magnetostriction, and Sagnac interferometry. We review the measurement of induced birefringence in the presence of natural birefringence. We propose the use of these effects in making measurements in the fusion research program, with ZT-40 as an example

  8. Polarization holographic recording in Disperse Red1 doped polyurethane polymer film

    Energy Technology Data Exchange (ETDEWEB)

    Aleksejeva, J; Gerbreders, A; Gertners, U; Reinfelde, M; Teteris, J, E-mail: aleksejeva.jelena@gmail.com [Institute of Solid State Physics, University of Latvia, Kengaraga street 8, Riga (Latvia)

    2011-06-23

    In this report holographic recording of polarisation and surface relief gratings in Disperse Red 1 (DR1) doped polyurethane polymer films was studied. In this material DR1 is chemically bounded to polyurethane polymer main chain. Polarization holographic recording was performed by two orthogonal circularly polarized 532 nm laser beams. Photoinduced birefringence is a precondition for polarization holograms recording, therefore a detailed study of a photoinduced birefringence and changes of optical properties was performed. The lasers with wavelengths of 375nm, 448nm, 532 nm and 632.8 nm were used as pumping beam for sample excitation. The photoinduced birefringence {Delta}n was measured at 532 nm and 632.8 nm wavelengths. The photoinduced birefringence dependence on the pumping beam wavelength and intensity was investigated. Surface relief grating (SRG) formation was observed during polarization holographic recording process. A profile of SRG was studied by AFM. A relationship between SRG formation and photoinduced birefringence has been discussed.

  9. Analysis of the collagen birefringence and the relative attenuation coefficient of health and burned skin irradiated with linearly polarized He-Ne laser; Analise da birrefringencia do colageno e do coeficiente de atenuacao de amostras de pele sadia e queimada irradiadas pelo laser de He-Ne linearmente polarizado

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Daniela de Fatima Teixeira da

    2002-07-01

    Low-intensity laser therapy is characterized by its ability to induce athermic effects and nondestructive photobiological processes. Although it has been in use for more than 40 years, this phototherapy is still not an established therapeutic modality. The objectives of this study were: to quantify the collagen fibers organization by polarized light microscopy in normal and burned skin samples at day 17 post-injury considering preferential axis as the animal's spinal column and aligning the linear laser polarization in two directions of polarization, parallel or perpendicular to this axis; to determine the relative attenuation coefficient for the intensity light by the technique of imaging the light distribution in normal and burned skin during wound healing process taking only parallel direction of polarization. To reach the objectives, burns about 6 mm in diameter were created with liquid N{sub 2} on the back of the rats and the lesions were irradiated on days 3, 7, 10 and 14 post-wounding, D= 1 J/cm{sup 2}, to investigate the effects of low-intensity linearly polarized He-Ne laser beam on skin wounds healing. Control lesions were not irradiated. The results have demonstrated that: the skin samples irradiated with linearly parallel polarized He-Ne laser beam showed collagen fibers more organized; burned skin samples presents a higher attenuation coefficient than normal skin samples. These results are important to optimize low intensity laser therapy dosimetry on acceleration wound healing. (author)

  10. Detection of ultrastructural changes in genetically altered and exercised skeletal muscle using PS-OCT

    Science.gov (United States)

    Pasquesi, James J.; Schlachter, Simon C.; Boppart, Marni D.; Chaney, Eric; Kaufman, Stephen J.; Boppart, Stephen A.

    2006-02-01

    Birefringence of skeletal muscle has been associated with the ultrastructure of individual sarcomeres, specifically the arrangement of A-bands corresponding to the thick myosin filaments. Murine skeletal muscle (gastrocnemius) was imaged with a fiber-based PS-OCT imaging system to determine the level of birefringence present in the tissue under various conditions. In addition to muscle controls from wild-type mice, muscle from abnormal mice included: genetically-modified (mdx) mice which model human muscular dystrophy, transgenic mice exhibiting an overexpression of integrin (α7β1), and transgenic integrin (α7β1)knockout mice. Comparisons were also made between rested and exercised muscles to determine the effects of exercise on muscle birefringence for each of these normal and abnormal conditions. The PS-OCT images revealed that the presence of birefringence was similar in the rested muscle with dystrophy-like features (i.e., lacking the structural protein dystrophin - mdx) and in the integrin (α7β1)knockout muscle when compared to the normal (wild-type) control. However, exercising these abnormal muscle tissues drastically reduced the presence of birefringence detected by the PS-OCT system. The muscle exhibiting an overexpression of integrin (α7β1) remained heavily birefringent before and after exercise, similar to the normal (wild-type) muscle. These results suggest that there is a distinct relationship between the degree of birefringence detected using PS-OCT and the sarcomeric ultrastructure present within skeletal muscle.

  11. In vivo detection of exercised-induced ultrastructural changes in genetically-altered murine skeletal muscle using polarization-sensitive optical coherence tomography

    Science.gov (United States)

    Boppart, Stephen

    2006-02-01

    Skeletal muscle fibers are a known source of form birefringence in biological tissue. The birefringence present in skeletal muscle is associated with the ultrastructure of individual sarcomeres, specifically the arrangement of A-bands corresponding to the thick myosin filaments. Certain structural proteins that prevent damage and maintain the structural and functional health of the muscle fiber preserve the organization of the Abands in skeletal muscle. Therefore, the level of birefringence detected can estimate the health of the muscle as well as the damage incurred during exercise. Murine skeletal muscle from both genetically-altered (mdx) and normal (wild-type) specimens were imaged in vivo with a fiber-based PSOCT imaging system to quantitatively determine the level of birefringence present in the tissue before and after exercise. The mdx muscle lacks dystrophin, a structural protein that is mutated in Duchenne muscular dystrophy in humans. Muscle from these mdx mice exhibited a marked decrease in birefringence after exercise, whereas the wild-type muscle was highly birefringent before and after exercise. The quantitative results from this tissue optics study suggest for the first time that there is a distinct relationship between the degree of birefringence detected using PS-OCT and the sarcomeric ultrastructure present within skeletal muscle.

  12. Electro-optic imaging Fourier transform spectrometer

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Znod, Hanying (Inventor)

    2009-01-01

    An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.

  13. Electromagnetic wave propagation in time-dependent media with antisymmetric magnetoelectric coupling

    Science.gov (United States)

    Lin, Shi-Rong; Zhang, Ruo-Yang; Ma, Yi-Rong; Jia, Wei; Zhao, Qing

    2016-07-01

    This paper deals with electromagnetic wave propagation in time-dependent media with an antisymmetric magnetoelectric coupling and an isotropic time-dependent permittivity. We identify a new mechanism of linear birefringence, originated from the combined action of the time-dependent permittivity and the antisymmetric magnetoelectric coupling. Permittivity with linear and exponential temporal variations exemplifies the creation and control of these two distinct types of linear birefringent modes. As a novel nonlinear optical effect, a scheme utilizing optical Kerr effect in moving media is proposed for the realization of the predicted birefringence.

  14. Nanogratings formation in multicomponent silicate glasses

    Science.gov (United States)

    Lancry, M.; Zimmerman, F.; Desmarchelier, R.; Tian, J.; Brisset, F.; Nolte, S.; Poumellec, B.

    2016-03-01

    We demonstrate the formation of porous nanogratings in various oxide glasses including TiO2-doped silica, GeO2 and alumino-borosilicate by near-IR femtosecond laser radiation. ULE and GeO2 glasses exhibit similar birefringence to pure silica, whereas Borofloat 33 reveals twice weaker amplitude. Using quantitative birefringence measurements, small-angle X-ray scattering and scanning electron microscopy, we correlate birefringence and porous nanolayers formation according to laser repetition rate and glass composition. We show that heat accumulation is a crucial parameter limiting the glass decomposition and thus nanogratings formation.

  15. Optical storage properties in cast films of an azopolymer

    Directory of Open Access Journals (Sweden)

    Neves Ubaldo Martins das

    2003-01-01

    Full Text Available In this paper we discuss the properties of optically induced birefringence in DR19-MDI cast films that may be used in optical storage applications. The selection of DR19-MDI cast films was based on a comparative study of optical storage properties of Langmuir-Blodgett (LB films from various azopolymers. DR19-MDI possesses a high residual fraction of optical birefringence and good environmental stability, which was corroborated by the data from optical storage experiments. DR19-MDI cast films maintain a reasonable level of birefringence after the initial decay due to chromophore relaxation, thus making them promising candidates for optical storage devices.

  16. Fabrication and characterization of V-groove liquid core waveguide

    Science.gov (United States)

    Nazari, T.; Khazaeinezhad, R.; Kassani, S. H.; Joo, B.; Suwal, O. K.; Hwang, J. H.; Paulson, B.; Park, J.; Oh, K.

    2015-07-01

    We report development of a new kind of micro-optical waveguide based on liquid core in a V-groove glass and air cladding and a similar finite element method was constructed to investigate the guiding properties such as mode distribution and modal birefringence. Through the detailed modeling, we investigate the role of each parameter such as, refractive index of core and diameter of core of V-groove structure. This work demonstrates numerically and experimentally high birefringence in this optical waveguide and different aspects of the fiber properties related to the fundamental mode and fiber birefringence are revealed. As a result, wave-guide with large birefringence is identified for opening angle of 40 degree and refractive index of 1.472.

  17. The 3-D collagen structure of equine articular cartilage, characterized using variable-angle-of-incidence polarization-sensitive optical coherence tomography

    Science.gov (United States)

    Ugryumova, Nadya; Gangnus, Sergei V.; Matcher, Stephen J.

    2005-08-01

    Polarization-sensitive optical coherence tomography has been used to spatially map the birefringence of equine articular cartilage. Images obtained in the vicinity of visible osteoarthritic lesions display a characteristic disruption of the regular birefringence bands shown by normal cartilage. We also note that significant (e.g. ×2) variations in the apparent birefringence of samples taken from young (18 month) animals that otherwise appear visually homogeneous are found over spatial scales of a few millimeters. We suggest that whilst some of this variation may be due to changes in the intrinsic birefringence of the tissue, the 3-D orientation of the collagen fibers relative to the plane of the joint surface should also be taken into account. We propose a method based on multiple angles of illumination to determine the polar angle of the collagen fibers.

  18. Variable angle-of-incidence polarization-sensitive optical coherence tomography: its use to study the 3D collagen structure of equine articular cartilage

    Science.gov (United States)

    Ugryumova, Nadya; Gangnus, Sergei V.; Matcher, Stephen J.

    2006-02-01

    Polarization-sensitive optical coherence tomography has been used to spatially map the birefringence of equine articular cartilage. The polar orientation of the collagen fibers relative to the plane of the joint surface must be taken into account if a quantitative measurement of true birefringence is required. Using a series of images taken at different angles of illumination, we determine the fiber polar angle and true birefringence at one site on a sample of equine cartilage, on the assumption that the fibers lie within the plane of imaging. We propose a more general method based on the extended Jones matrix formalism to determine both the polar and azimuthal orientation of the collagen fibers as well as the true birefringence as functions of depth.

  19. Accelerating airy beams generated by ultrafast laser induced space-variant nanostructures in glass

    OpenAIRE

    Gecevičius, M.; M. Beresna; Kazansky, P. G.

    2012-01-01

    We demonstrate new technique to generate accelerating Airy beam with femtosecond laser imprinted space variant birefringence produced by self-assembled nanostructures in fused silica. The technique enables dual Airy beam generation.

  20. Full vectorial analysis of multilayer leaky cladding optical fibre

    CERN Document Server

    Labonté, Laurent; Kumar, A; Dussardier, Bernard; Monnom, Gérard

    2010-01-01

    We analyze a multilayer leaky cladding (MLC) fibre using the finite element method and study the effect of the MLC on the bending loss and birefringence of two types of structures: i) a circular-core large-mode area structure and ii) an elliptical-small-core structure. In a large-mode-area structure, we verify that the multi-layer leaky cladding strongly discriminates against higher order modes to achieve single-mode operation, the fibre shows negligible birefringence, and the bending loss of the fibre is low for bending radii larger than 10 cm. In the elliptical-small-core structure we show that the MLC reduces the birefringence of the fibre. This prevents the structure from becoming birefringent in case of any departures from circular geometry. The study should be useful in the designs of MLC fibres for various applications including high-power amplifiers, gain flattening of fibre amplifiers and dispersion compensation.

  1. Polarization Maintaining Hybrid TIR/Bandgap All-Solid Photonic Crystal Fiber

    DEFF Research Database (Denmark)

    Lyngsøe, Jens Kristian; Mangan, Brian J.; Roberts, John

    2008-01-01

    We report on fabricated all-solid fibers which guide by a combination of bandgap and TIR mechanisms. The fibers show high birefringence and possess a dispersion characteristic similar to the pure bandgap guiding form....

  2. 5D data storage by ultrafast laser nanostructuring in glass

    OpenAIRE

    Zhang, J.; Gecevičius, M.; Beresna, M.; Kazansky, P.G.

    2013-01-01

    The high-density five dimensional data storage with ultrafast laser writing is demonstrated. The text file is recorded by polarization controlled self-assembled form birefringence and retrieved in glass opening the era of unlimited lifetime data storage

  3. Ferrofluid viscometer

    OpenAIRE

    Bacri, J. -C.; Dumas, J.; Gorse, D.; Perzynski, R.; Salin, D.

    1985-01-01

    The alignment of magnetic colloidal particles along a magnetic field induces a birefringence of the solution. As the magnetic field is switched off, this birefringence level relaxes to zero with a characteristic time proportional to the viscosity of the solution. The measurement of this relaxation time gives the value of the viscosity with a relative accuracy of 5 % and over a viscosity range of seven decades.

  4. Polarization properties of photonic bandgap fibers

    DEFF Research Database (Denmark)

    Broeng, Jes; Libori, Stig E. Barkou; Bjarklev, Anders Overgaard

    2000-01-01

    We present the first analysis of polarization properties of photonic bandgap fibers. Strong birefringence may be obtained for modest non-uniformities in and around the core region, suggesting the use of photonic bandgap fibers as polarization maintaining components.......We present the first analysis of polarization properties of photonic bandgap fibers. Strong birefringence may be obtained for modest non-uniformities in and around the core region, suggesting the use of photonic bandgap fibers as polarization maintaining components....

  5. Quasi-phase-matching of high-order-harmonic generation using polarization beating in optical waveguides

    OpenAIRE

    Liu, Lewis Z.; O'Keeffe, Kevin; Hooker, Simon M.

    2013-01-01

    A scheme for quasi-phase-matching high-harmonic generation is proposed in which polarization beating within a hollow core birefringent waveguide modulates the generation of harmonics. The evolution of the polarization of a laser pulse propagating in a birefringent waveguide is calculated and is shown to periodically modulate the harmonic generation process. The optimum conditions for achieving quasi-phase-matching using this scheme are explored and the growth of the harmonic intensity as a fu...

  6. Measurement of optical activity of honey bee

    Science.gov (United States)

    Ortiz-Gutiérrez, Mauricio; Olivares-Pérez, Arturo; Salgado-Verduzco, Marco Antonio; Ibarra-Torres, Juan Carlos

    2016-03-01

    Optical activity of some substances, such as chiral molecules, often exhibits circular birefringence. Circular birefringence causes rotation of the vibration plane of the plane polarized light as it passes through the substance. In this work we present optical characterization of honey as function of the optical activity when it is placed in a polariscope that consists of a light source and properly arranged polarizing elements.

  7. Terahertz polarization conversion with quartz waveplate sets.

    Science.gov (United States)

    Kaveev, Andrey K; Kropotov, Grigory I; Tsygankova, Ekaterina V; Tzibizov, Ivan A; Ganichev, Sergey D; Danilov, Sergey N; Olbrich, Peter; Zoth, Christina; Kaveeva, Elizaveta G; Zhdanov, Alexander I; Ivanov, Andrey A; Deyanov, Ramil Z; Redlich, Britta

    2013-02-01

    We present the results of calculation and experimental testing of an achromatic polarization converter and a composite terahertz waveplate (WP), which are represented by sets of plane-parallel birefringent plates with in-plane birefringence axis. The calculations took into account the effect of interference, which was especially prominent when plates were separated by an air gap. The possibility of development of a spectrum analyzer design based on a set of WPs is also discussed. PMID:23385943

  8. Tunable wavelength terahertz polarization converter based on quartz waveplates.

    Science.gov (United States)

    Kaveev, A K; Kropotov, G I; Tsypishka, D I; Tzibizov, I A; Vinerov, I A; Kaveeva, E G

    2014-08-20

    We present the results of calculation and experimental testing of the tunable wavelength terahertz polarization converter represented by a set of plane-parallel birefringent plates with an in-plane birefringence axis. An experimental device has been produced and tested. The calculations show that the effect of interference between the interfaces, including air gaps, may be neglected. The considered device may be used as a simple narrow achromatic waveplate, or a Solc band pass filter for the specified wavelength. PMID:25321112

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

    DEFF Research Database (Denmark)

    Sajti, Sz.; Kerekes, Á.; Barabás, M.; Lorincz, E; Hvilsted, Søren; Ramanujam, P.S.

    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. It i...... shown that the anisotropy is not erased, only the direction of the optical axis is changed, and this is measured as erasure. The computed results are compared with measurements and show good agreement for several intensities....

  10. Evolution and the Calcite Eye Lens

    CERN Document Server

    Williams, Vernon L

    2013-01-01

    Calcite is a uniaxial, birefringent crystal, which in its optically transparent form, has been used for animal eye lenses, the trilobite being one such animal. Because of the calcite birefringence there is a difficulty in using calcite as a lens. When the propagation direction of incoming light is not exactly on the c-axis, the mages blur. In this paper, calcite blurring is evaluated, and the non-blurring by a crystallin eye lens is compared to a calcite one.

  11. Extreme Outages due to Polarization Mode Dispersion Effects of Optical Filter and "Setting the Clock" Compensation

    CERN Document Server

    Chernyak, V; Kolokolov, I V; Lebedev, V; Chernyak, Vladimir; Chertkov, Michael; Kolokolov, Igor; Lebedev, Vladimir

    2003-01-01

    Dependence of the bit-error-rate (BER) caused by amplifier noise in a linear fiber optics line on the fiber birefringence is investigated. We show that the probability distribution function (PDF) of BER obtained by averaging over many realizations of birefringent disorder has an extended tail corresponding to anomalously large values of BER. We specifically discuss dependence of the tail on such details of pulse detection at the fiber output as "setting the clock" and filtering procedures.

  12. Fresnel analysis of the wave propagation in nonlinear electrodynamics

    OpenAIRE

    Obukhov, Yuri N.; Rubilar, Guillermo F.

    2002-01-01

    We study the wave propagation in nonlinear electrodynamical models. Particular attention is paid to the derivation and the analysis of the Fresnel equation for the wave covectors. For the class of general nonlinear Lagrangian models, we demonstrate how the originally quartic Fresnel equation factorizes, yielding the generic birefringence effect. We show that the closure of the effective constitutive (or jump) tensor is necessary and sufficient for the absence of birefringence, i.e., for the e...

  13. A histochemical and electron microscopic study on the collagen of nerves in the domestic fowl.

    OpenAIRE

    Luque, E H; Angulo, E.; Montes, G S

    1983-01-01

    The collagen in the endoneurium is present as argyrophilic reticular fibres, which show up as thin, weakly birefringent greenish fibres when studied by aid of the Picrosirius-polarization method, and are composed of loosely arranged thin collagen fibrils. The epineurium consists of thick non-argyrophilic collagen fibres, which display a strong birefringence of red or yellow colour when studied by the aid of the Picrosirius-polarization method, and consist of closely packed thick collagen fibr...

  14. Design of twisted-nematic liquid crystal displays for holographic data storage

    OpenAIRE

    Fernández Varó, Elena; Márquez Ruiz, Andrés; Pérez Molina, Manuel; Fuentes Rosillo, Rosa; García Llopis, Celia; Francés Monllor, Jorge; Pascual Villalobos, Inmaculada

    2010-01-01

    This work describes an ideal design of a nematic liquid crystal display (TN-LCD) that allows obtaining the best configuration of a hybrid ternary modulation to be applied in holographic data storage. With this purpose, the thickness of a real LCD was modified in order to change the birefringence versus gray level. With these new birefringences, simulations for different configurations were made to design an LCD having a HTM as close as possible to the ideal one.

  15. Photorefractive optical processing: some proposals

    OpenAIRE

    Ángel-Toro, Luciano; Bolgnini, Néstor; Tebaldi, Myrian

    1999-01-01

    Some proposals on Lau and Talbot fringes formation based on a grating registered as birefringence modulation in a photorefractive crystal, will be presented. In the Talbot case, the stored grating can be replicated if read-out with coherent light. The system for the Lau arrangement behaves as a combination of an amplitude and a birefringence phase grating. In both cases, it is possible to control the visibility and to produce a contrast reversion of fringes by using an analyzer. Besides, Lau ...

  16. Current sensing in magnetic fusion experiments by Faraday rotation in single-mode optical fibers

    International Nuclear Information System (INIS)

    We find that sensors exploiting the Faraday effect in single-mode optical fibers are practical means of measuring large currents in the MFE environment. Work still needs to be done to overcome the effects of linear birefringence. We have seen distortion caused by dynamic stress-induced birefringence and shown the importance of physically eliminating it because of the difficulty of treating it analytically

  17. Injection-compression and co-injection moldings of amorphous polymers: Viscoelastic simulation and experiment

    Science.gov (United States)

    Kim, Nam Hyung

    Injection-compression molding (ICM) and co-injection molding have gained increasing importance in manufacturing of polymer products. Scientific understanding of these processes is presently limited and no attempts have been made to simulate co-injection molding using a viscoelastic model. In addressing this issue, the present study provides results of comprehensive viscoelastic simulations and experimental investigations of the residual stresses and birefringence in center-gated disk moldings of amorphous polymers obtained by ICM and sequential co-injection molding (SCIM) at various processing conditions. The governing equations for viscoelastic simulation of ICM and SCIM processes were derived using a nonlinear viscoelastic model. The equations were solved using a hybrid control volume/finite element/finite difference method. In general, residual stresses and birefringence in moldings arise from the flow- and thermally-induced contributions. To consider the thermal contribution, simulations and experimental study of birefringence in freely quenched multi-layered plates were carried out. The flow- and thermally-induced stresses were simulated using nonlinear and linear viscoelastic theories, respectively. The overall residual birefringence in moldings was obtained by summation of the flow- and thermally-induced birefringence contributions calculated using the stress-optical rule and photoviscoelastic constitutive equation, respectively. The numerical results were found to be in fair agreement with experimental data on the distribution of residual birefringence, Deltan, and average transverse birefringence, , of the ICM made from polycarbonate (PC) and polystyrene (PS). It was found that the melt temperature and compression stroke strongly affected the residual birefringence in ICM, while the mold temperature had less effect. The numerical and experimental results of the gapwise distribution of the residual birefringence, Delta n, and interface of the SCIM were

  18. A Mach-Zehnder interferometer based on orbital angular momentum for improved vortex coronagraph efficiency

    Science.gov (United States)

    Piron, P.; Delacroix, C.; Huby, E.; Mawet, D.; Karlsson, M.; Ruane, G.; Habraken, S.; Absil, O.; Surdej, J.

    2015-09-01

    The Annular Groove Phase Mask (AGPM) is a vectorial vortex phase mask. It acts as a half-wave plate with a radial fast axis orientation operating in the mid infrared domain. When placed at the focus of a telescope element provides a continuous helical phase ramp for an on axis sources, which creates the orbital angular momentum. Thanks to that phase, the intensity of the central source is canceled by a down-stream pupil stop, while the off axis sources are not affected. However due to experimental conditions the nulling is hardly perfect. To improve the null, a Mach-Zehnder interferometer containing Dove prisms differently oriented can be proposed to sort out light based on its orbital angular momentum (OAM). Thanks to the differential rotation of the beam, a π phase shift is achieved for the on axis light affected by a non zero OAM. Therefore the contrast between the star and its faint companion is enhanced. Nevertheless, due the Dove prisms birefringence, the performance of the interferometer is relatively poor. To solve this problem, we propose to add a birefringent wave-plate in each arm to compensate this birefringence. In this paper, we will develop the mathematical model of the wave front using the Jones formalism. The performance of the interferometer is at first computed for the simple version without the birefringent plate. Then the effect of the birefringent plate is be mathematically described and the performance is re-computed.

  19. Simultaneous oblique deposition from opposite azimuthal directions for fabrication of thin film retardation plates

    Science.gov (United States)

    Motohiro, Tomoyoshi; Takeda, Yasuhiko; Hioki, Tatsumi; Noda, Shoji

    1996-08-01

    Obliquely vapor deposited thin film (OVD-TF) is characterized by its unique inclined columnar structure (ICS). In previous work, the form birefringence originated from ICS was utilized to form amorphous Ta2O5 thin film retardation plates (TF-RPs). By reducing the size of ICS in nm scale range, the film was durable and transparent getting rid of the haze inherent in usual OVD-TF. In the present work, again TF-RPs were formed on fused silica substrates but this time by simultaneous oblique deposition from two Ta2O5 sputtering sources located at opposite azimuthal directions in a specially designed sputter-deposition apparatus. A typical birefringence obtained was (Delta) n equals 0.087, 0.049 and 0.043 at the wavelength of 300 nm, 500 nm and 800 nm, respectively. A film of 2550 nm thick can make a quarter wave plate at 500 nm. The columnar structure which inclined no more this time does not cause birefringence for a normally incident light. The birefringence comes this time from the fact that the columns are less closely spaced in the plane of the vapor incidence (PVI) than normal to PVI. This is the first example that the birefringence of this type is utilized to fabricate TF-RPs. The growth mechanism of this anisotropic nm scale structure was discussed with 3D-simulation of ballistic deposition.

  20. Using polarization-sensitive optical coherence tomography to identify tumor stromal fibrosis and increase tumor biopsy yield (Conference Presentation)

    Science.gov (United States)

    Hariri, Lida P.; Adams, David C.; Miller, Alyssa J.; Mino-Kenudson, Mari; Suter, Melissa J.

    2016-03-01

    Tissue biopsy is the principal method used to diagnose tumors in a variety of organ systems. It is essential to maximize tumor yield in biopsy specimens for both clinical diagnostic and research purposes. This is particularly important in tumors where additional tissue is needed for molecular analysis to identify patients who would benefit from mutation-specific targeted therapy, such as in lung carcinomas. Inadvertent sampling of fibrotic stroma within tumor nodules contaminates biopsies, decreases tumor yield, and can impede diagnosis. The ability to assess tumor composition and guide biopsy site selection in real time is likely to improve diagnostic yield. Polarization sensitive OCT (PS-OCT) measures birefringence in organized tissues, such as collagen, and could be used to distinguish tumor from fibrosis. In this study, PS-OCT was obtained in 65 lung nodule samples from surgical resection specimens containing varying ratios of tumor and fibrosis. PS-OCT was obtained with either a custom-built helical scanning catheter (0.8 or 1.6mm in diameter) or a dual-axis bench top scanner. Strong birefringence was observed in nodules containing dense fibrosis, with no birefringence in adjacent regions of tumor. Tumors admixed with early, loosely-organized collagen demonstrated mild-to-moderate birefringence, and tumors with little collagen content showed little to no birefringent signal. PS-OCT provides significant insights into tumor nodule composition, and has potential to differentiate tumor from stromal fibrosis during biopsy site selection to increase diagnostic tumor yield.

  1. Digitally Reinforced Polarization of Hematoxylin-Eosin in the Diagnosis of Renal Amyloidosis

    Directory of Open Access Journals (Sweden)

    Sait ŞEN

    2012-09-01

    Full Text Available Objective: Systemic amyloidosis is a rare disorder, characterized by extracellular accumulation of Congo red positive fibrillar amyloid protein deposits that have an amorphous, eosinophilic appearance on hematoxylin-eosin stained preparations. The kidney is the most commonly affected organ by systemic amyloidosis. Congo red staining increases the positive birefringence of the weakly birefringent unstained amyloid. In this study, we investigated the potential diagnostic power of digitally reinforced birefringence of routine hematoxylin-eosin stained slides from renal biopsies.Material and Method: We reviewed 130 hematoxylin-eosin stained slides for polarization. Sixty-five new amyloidosis cases were diagnosed by renal biopsy. All renal biopsies were evaluated by light microscopy and immunofluorescence. Slides were reevaluated blindly using a microscope (Olympus BX51 that was attached polarization filters and connected to a digital camera (Olympus DP21, SAL. Deposits that showed green birefringence on hematoxylin-eosin preparations with digitalized microscopy were considered positive and the results were confirmed using Congo red.Results: Of the 65 Congo red confirmed amyloid positive biopsies, 61 showed green birefringence with hematoxylin-eosin. Of the 65 Congo-red confirmed amyloid negative biopsies, two were considered to be false positive. The sensitivity, specificity, and positive and negative predictive values were estimated as 94%, 97%, 97% and 94% respectively.Conclusion: We concluded that polarized hematoxylin-eosin sections can be used digitally as a fast and first step diagnostic method for renal amyloidosis

  2. Great circle solution to polarization-based quantum communication (QC) in optical fiber

    Science.gov (United States)

    Nordholt, Jane Elizabeth; Peterson, Charles Glen; Newell, Raymond Thorson; Hughes, Richard John

    2016-03-15

    Birefringence in optical fibers is compensated by applying polarization modulation at a receiver. Polarization modulation is applied so that a transmitted optical signal has states of polarization (SOPs) that are equally spaced on the Poincare sphere. Fiber birefringence encountered in propagation between a transmitter and a receiver rotates the great circle on the Poincare sphere that represents the polarization bases used for modulation. By adjusting received polarizations, polarization components of the received optical signal can be directed to corresponding detectors for decoding, regardless of the magnitude and orientation of the fiber birefringence. A transmitter can be configured to transmit in conjugate polarization bases whose SOPs can be represented as equidistant points on a great circle so that the received SOPs are mapped to equidistant points on a great circle and routed to corresponding detectors.

  3. Loop-mirror-based slot waveguide refractive index sensor

    Science.gov (United States)

    Kou, Jun-long; Xu, Fei; Lu, Yan-qing

    2012-12-01

    Loop mirror has been widely used in fiber optical devices and systems for it provides a smart way to make use of the fiber birefringence properties and can enhance the sensitivity greatly. On the other hand, slot waveguide is very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper, we propose and analyze a loop-mirror-based slot waveguide (LMSW) sensor which can be routinely fabricated in modern high-volume complementary metal-oxide-semiconductor (CMOS) process. The finite element method (FEM) simulation results show that the birefringence can be as high as 0.8 which is orders of magnitude than that in conventional birefringent fiber loop mirror. High sensitivity up to 6 × 103 nm/RIU (refractive index unit) is achieved by this scheme.

  4. Loop-mirror-based slot waveguide refractive index sensor

    Directory of Open Access Journals (Sweden)

    Jun-long Kou

    2012-12-01

    Full Text Available Loop mirror has been widely used in fiber optical devices and systems for it provides a smart way to make use of the fiber birefringence properties and can enhance the sensitivity greatly. On the other hand, slot waveguide is very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper, we propose and analyze a loop-mirror-based slot waveguide (LMSW sensor which can be routinely fabricated in modern high-volume complementary metal-oxide–semiconductor (CMOS process. The finite element method (FEM simulation results show that the birefringence can be as high as 0.8 which is orders of magnitude than that in conventional birefringent fiber loop mirror. High sensitivity up to 6 × 103 nm/RIU (refractive index unit is achieved by this scheme.

  5. The collagen structure of equine articular cartilage characterized using polarization-sensitive optical coherence tomography and non-linear microscopy

    Science.gov (United States)

    Mansfield, Jessica C.; Ugryumova, Nadya; Knapp, Karen M.; Matcher, Stephen J.

    2006-09-01

    Equine articular cartilage has been imaged using both polarization-sensitive optical coherence tomography (PS-OCT) and non-linear microscopy. PS-OCT has been used to spatially map the birefringence in the cartilage and we have found that in the vicinity of the lesion the images display a characteristic disruption in the regular birefringence bands shown by normal cartilage. We also note that significant (e.g. x2) variations in the apparent birefringence of samples taken from young (18 month) animals that otherwise appear visually homogeneous are found over spatial scales of a few millimeters. We have also imaged the cartilage using non-linear microscopy and compare the scans taken with second harmonic generation (SHG) light and the two photon fluorescence (TPF) light. SHG images collected using 800 nm excitation reveals the spatial distribution of collagen fibers, whilst TPF images clearly shows the distribution of intracellular and pericellular fluorophores.

  6. Effects of Pamidronate on Dental Enamel Formation Assessed by Light Microscopy, Energy-Dispersive X-Ray Analysis, Scanning Electron Microscopy, and Microhardness Testing.

    Science.gov (United States)

    Soares, Ana P; do Espírito Santo, Renan F; Line, Sérgio R P; Pinto, Maria das G F; Santos, Pablo de M; Toralles, Maria Betania P; do Espírito Santo, Alexandre R

    2016-06-01

    The aim of the present work was to investigate birefringence and morphology of the secretory-stage enamel organic extracellular matrix (EOECM), and structural and mechanical properties of mature enamel of upper incisors from adult rats that had been treated with pamidronate disodium (0.5 mg/kg/week for 56 days), using transmitted polarizing and bright-field light microscopies (TPLM and BFLM), energy-dispersive X-ray (EDX) analysis, scanning electron microscopy (SEM) and microhardness testing. BFLM showed no morphological changes of the EOECM in pamidronate and control groups, but TPLM revealed a statistically significant reduction in optical retardation values of birefringence brightness of pamidronate-treated rats when compared with control animals (p0.05). The present study indicates that pamidronate can affect birefringence of the secretory-stage EOECM, which does not seem to be associated with significant changes in morphological and/or mechanical properties of mature enamel. PMID:27212049

  7. Frequency tuning of polarization oscillations: Toward high-speed spin-lasers

    Energy Technology Data Exchange (ETDEWEB)

    Lindemann, Markus, E-mail: markus.lindemann@rub.de; Gerhardt, Nils C.; Hofmann, Martin R. [Photonics and Terahertz Technology, Ruhr-University Bochum, 44780 Bochum (Germany); Pusch, Tobias; Michalzik, Rainer [Institute of Optoelectronics, Ulm University, 89081 Ulm (Germany)

    2016-01-25

    Spin-controlled vertical-cavity surface-emitting lasers (spin-VCSELs) offer a high potential to overcome several limitations of conventional purely charged-based laser devices. Presumably, the highest potential of spin-VCSELs lies in their ultrafast spin and polarization dynamics, which can be significantly faster than the intensity dynamics in conventional devices. Here, we experimentally demonstrate polarization oscillations in spin-VCSELs with frequencies up to 44 GHz. The results show that the oscillation frequency mainly depends on the cavity birefringence, which can be tuned by applying mechanical strain to the VCSEL structure. A tuning range of about 34 GHz is demonstrated. By measuring the polarization oscillation frequency and the birefringence governed mode splitting as a function of the applied strain simultaneously, we are able to investigate the correlation between birefringence and polarization oscillations in detail. The experimental findings are compared to numerical calculations based on the spin-flip model.

  8. Slow wave cavity resonance in periodic stacks of anisotropic layers

    CERN Document Server

    Figotin, Alex

    2007-01-01

    We consider Fabry-Perot cavity resonance in periodic layered structures involving birefringent layers. Previously we have shown that the presence of birefringent layers with misaligned in-plane anisotropy can dramatically enhance the performance of the photonic-crystal cavity. It allows to reduce the size of a Fabry-Perot resonator by an order of magnitude without compromising on its performance. The key characteristic of the enhanced photonic-crystal cavity is that its Bloch dispersion relation displays a degenerate photonic band edge, rather than only regular ones. This can be realized in specially arranged stacks of misaligned anisotropic layers. On the down side, the presence of birefringent layers results in the Fabry-Perot resonance being coupled only with one (elliptic) polarization component of the incident wave, while the other polarization component is reflected back to space. In this paper we show how a small modification of the periodic layered array can solve the above fundamental problem and pro...

  9. A new kinetic description of the complex optical behavior in photochromic polymer films

    International Nuclear Information System (INIS)

    Kinetics of photoinduced birefringence in precolored spirooxazine-doped polymer films pumped with He-Ne laser beams of various powers was investigated in detail. An improved model, elucidating a competition between photo-orientation and photo-isomerization, was precisely presented. Kinetic parameters determined by fitting to the experimental data were analyzed. As He-Ne laser intensity is increased, the thermal rate constants for isomerization and randomization increase in linear and exponential fashions, respectively. Taking these factors into account, the Thermal Effect Model was more suitable for describing the experiment than the Constant Model, indicating that thermal effect of He-Ne laser plays a key role in decreasing the saturated birefringence. According to the Thermal Effect Model, the highest value of the saturated birefringence was obtained at the He-Ne laser power of 6.5 mW in our experiment

  10. A double image Mach-Zehnder interferometer

    Science.gov (United States)

    Ramadan, W. A.; El-Tawargy, A. S.

    2015-02-01

    In this paper, we present a modified version of the Mach-Zehnder interferometer. An arrangement of two linear polarizers and a wave rotator has been inserted in the light's path. Using this new arrangement, we are able to obtain a double image of a birefringent fibre. This double image records the shifts of the Mach-Zehnder's fringes for the light vibrating parallel and perpendicular to the fibre's axis in the same image. Moreover, by controlling the beam splitters, we are able to get an overlap between two images of the fibre and to directly observe an image describing the birefringence of the investigated fibre. This new arrangement has been applied to three polypropylene fibres and a graded-index FOS optical fibre in order to demonstrate its validity and powerful ability for monitoring the direct birefringence. A set of images of the investigated samples is presented and compared with images obtained using the classical Mach-Zehnder interferometer.

  11. A Jones matrix formalism for simulating 3D Polarised Light Imaging of brain tissue

    CERN Document Server

    Menzel, Miriam; De Raedt, Hans; Reckfort, Julia; Amunts, Katrin; Axer, Markus

    2015-01-01

    The neuroimaging technique 3D Polarised Light Imaging (3D-PLI) provides a high-resolution reconstruction of nerve fibres in human post-mortem brains. The orientations of the fibres are derived from birefringence measurements of histological brain sections assuming that the nerve fibres - consisting of an axon and a surrounding myelin sheath - are uniaxial birefringent and that the measured optic axis is oriented in direction of the nerve fibres (macroscopic model). Although experimental studies support this assumption, the molecular structure of the myelin sheath suggests that the birefringence of a nerve fibre can be described more precisely by multiple optic axes oriented radially around the fibre axis (microscopic model). In this paper, we compare the use of the macroscopic and the microscopic model for simulating 3D-PLI by means of the Jones matrix formalism. The simulations show that the macroscopic model ensures a reliable estimation of the fibre orientations as long as the polarimeter does not resolve ...

  12. Optical time-domain differentiation based on intensive differential group delay

    Institute of Scientific and Technical Information of China (English)

    Li Zheng-Yong; Yu Xiang-Zhi; Wu Chong-Qing

    2011-01-01

    An optical time-domain differentiation scheme is proposed and demonstrated based on the intensive differential group delay in a high birefringence fibre waveguide.Results show that the differentiation waveforms agree well with the mathematically calculated derivatives.Both error and efficiency will increase when the birefringence fibre becomes longer,and the error rises up more quickly while the efficiency approaches to a maximum of ~0.25.By using a 1-m birefringence fibre a lower error of ~0.26% is obtained with an efficiency of 1% for the first-order differentiation of 10-ps Gaussian optical pulses,and the high-order optical differentiation up to 4th order is achieved with an error less than 3%.Due to its compact structure being easy to integrate and cascade into photonic circuits,our scheme has great potential for ultrafast signal processing.

  13. Scalar - vector soliton fiber lasers

    CERN Document Server

    Wu, Zhichao; Li, Lei; Luo, Yiyang; Tang, Dingyuan; Shen, Deyuan; Tang, Ming; Fu, Songnian; Zhao, Luming

    2016-01-01

    Rapid progress in passively mode-locked fiber lasers is currently driven by the recent discovery of vector feature of mode-locking pulses, namely, the group velocity-locked vector solitons, the phase locked vector solitons, and the high-order vector solitons. Those vector solitons are fundamentally different from the previously known scalar solitons. Here, we report a fiber laser where the mode-locked pulse evolves as a vector soliton in the strong birefringent segment and is transformed into a regular scalar soliton after the polarizer within the laser cavity. The existence of solutions in a polarization-dependent cavity comprising a periodic combination of two distinct nonlinear waves is novel and likely to be applicable to various other nonlinear systems. For very large local birefringence, our laser approaches the working regime of vector soliton lasers, while it approaches scalar soliton fiber lasers under the conditions of very small birefringence.

  14. Frequency tuning of polarization oscillations: Toward high-speed spin-lasers

    International Nuclear Information System (INIS)

    Spin-controlled vertical-cavity surface-emitting lasers (spin-VCSELs) offer a high potential to overcome several limitations of conventional purely charged-based laser devices. Presumably, the highest potential of spin-VCSELs lies in their ultrafast spin and polarization dynamics, which can be significantly faster than the intensity dynamics in conventional devices. Here, we experimentally demonstrate polarization oscillations in spin-VCSELs with frequencies up to 44 GHz. The results show that the oscillation frequency mainly depends on the cavity birefringence, which can be tuned by applying mechanical strain to the VCSEL structure. A tuning range of about 34 GHz is demonstrated. By measuring the polarization oscillation frequency and the birefringence governed mode splitting as a function of the applied strain simultaneously, we are able to investigate the correlation between birefringence and polarization oscillations in detail. The experimental findings are compared to numerical calculations based on the spin-flip model

  15. Optical time-domain differentiation based on intensive differential group delay

    International Nuclear Information System (INIS)

    An optical time-domain differentiation scheme is proposed and demonstrated based on the intensive differential group delay in a high birefringence fibre waveguide. Results show that the differentiation waveforms agree well with the mathematically calculated derivatives. Both error and efficiency will increase when the birefringence fibre becomes longer, and the error rises up more quickly while the efficiency approaches to a maximum of ∼0.25. By using a 1-m birefringence fibre a lower error of ∼0.26% is obtained with an efficiency of 1% for the first-order differentiation of 10-ps Gaussian optical pulses, and the high-order optical differentiation up to 4th order is achieved with an error less than 3%. Due to its compact structure being easy to integrate and cascade into photonic circuits, our scheme has great potential for ultrafast signal processing. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  16. Fabrication of microchannels in fused silica using femtosecond Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Yashunin, D. A., E-mail: yashuninda@yandex.ru [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Str., Nizhny Novgorod 603950 (Russian Federation); Nizhny Novgorod State Technical University, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation); Malkov, Yu. A. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Str., Nizhny Novgorod 603950 (Russian Federation); Mochalov, L. A.; Stepanov, A. N. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Str., Nizhny Novgorod 603950 (Russian Federation); Nizhny Novgorod State Technical University, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation)

    2015-09-07

    Extended birefringent waveguiding microchannels up to 15 mm long were created inside fused silica by single-pulse irradiation with femtosecond Bessel beams. The birefringent refractive index change of 2–4 × 10{sup −4} is attributed to residual mechanical stress. The microchannels were chemically etched in KOH solution to produce 15 mm long microcapillaries with smooth walls and a high aspect ratio of 1:250. Bessel beams provide higher speed of material processing compared to conventional multipulse femtosecond laser micromachining techniques and permit simple control of the optical axis direction of the birefringent waveguides, which is important for practical applications [Corrielli et al., “Rotated waveplates in integrated waveguide optics,” Nat. Commun. 5, 4249 (2014)].

  17. Orthogonality breaking sensing model based on the instantaneous Stokes vector and the Mueller calculus

    CERN Document Server

    Ortega-Quijano, Noé; Roche, Muriel; Parnet, François; Alouini, Mehdi

    2015-01-01

    Polarimetric sensing by orthogonality breaking has been recently proposed as an alternative technique for performing direct and fast polarimetric measurements using a specific dual-frequency dual-polarization (DFDP) source. Based on the instantaneous Stokes-Mueller formalism to describe the high-frequency evolution of the DFDP beam intensity, we thoroughly analyze the interaction of such a beam with birefringent, dichroic and depolarizing samples. This allows us to confirm that orthogonality breaking is produced by the sample diattenuation, whereas this technique is immune to both birefringence and diagonal depolarization. We further analyze the robustness of this technique when polarimetric sensing is performed through a birefringent waveguide, and the optimal DFDP source configuration for fiber-based endoscopic measurements is subsequently identified. Finally, we consider a stochastic depolarization model based on an ensemble of random linear diattenuators, which makes it possible to understand the progress...

  18. Anisotropy in Thermo-Optic Coefficient of Different Polymer Systems by Attenuated Total Reflection Configuration

    Institute of Scientific and Technical Information of China (English)

    LI Xiang; CAO Zhuang-Qi; SHEN Qi-Shun; MENG Qing-Hua; HUANG De-Ying; GUO Kun-Peng; QIU Ling; SHEN Yu-Quan

    2006-01-01

    @@ Thermo-optic coefficient dn/dT as well as volume expansion coefficients β of different polymer systems are measured for both TE and TM polarizations in an attenuated total reflection (ATR) configuration. Experimental results indicate that cross-linked polymer systems exhibit the thermal expansion coefficients smaller than those of the original side-chain systems. Moreover, the anisotropies in thermo-optic coefficients of the polymer systems with small birefringence exhibit linear relationship with the anisotropies in volume expansion coefficients, but the polymer systems with larger birefringence exhibit more complicated relationship.

  19. Enhanced magnetic-field-induced optical properties of nanostructured magnetic fluids by doping nematic liquid crystals

    OpenAIRE

    Wang, Xiang; Pu, Shengli; Ji, Hongzhu; YU, GUOJUN

    2012-01-01

    Ferronematic materials composed of 4-cyano-4′-pentylbiphenyl nematic liquid crystal and oil-based Fe3O4 magnetic fluid were prepared using ultrasonic agitation. The birefringence (Δn) and figure of merit of optical properties (Q = Δn/α, where α is the extinction coefficient) of pure magnetic fluids and the as-prepared ferronematic materials were examined and compared. The figure of merit of optical properties weighs the birefringence and extinction of the materials and is more appropriate to ...

  20. Versatile transmission ellipsometry to study linear ferrofluid magneto-optics.

    Science.gov (United States)

    Kooij, E S; Gâlcă, A C; Poelsema, B

    2006-12-01

    Linear birefringence and dichroism of magnetite ferrofluids are studied simultaneously using spectroscopic ellipsometry in transmission mode. It is shown that this versatile technique enables highly accurate characterisation of magneto-optical phenomena. Magnetic field-dependent linear birefringence and dichroism as well as the spectral dependence are shown to be in line with previous results. Despite the qualitative agreement with established models for magneto-optical phenomena, these fail to provide an accurate, quantitative description of our experimental results using the bulk dielectric function of magnetite. We discuss the results in relation to these models, and indicate how the modified dielectric function of the magnetite nanoparticles can be obtained. PMID:16997315

  1. The collagen structure of equine articular cartilage, characterized using polarization-sensitive optical coherence tomography

    Science.gov (United States)

    Ugryumova, Nadya; Attenburrow, Don P.; Winlove, C. Peter; Matcher, Stephen J.

    2005-08-01

    Optical coherence tomography and polarization-sensitive optical coherence tomography images of equine articular cartilage are presented. Measurements were made on intact joint surfaces. Significant (e.g. × 2) variations in the intrinsic birefringence were found over spatial scales of a few millimetres, even on samples taken from young (18 month) animals that appeared visually homogeneous. A comparison of data obtained on a control tissue (equine flexor tendon) further suggests that significant variations in the orientation of the collagen fibres relative to the plane of the joint surface exist. Images of visually damaged cartilage tissue show characteristic features both in terms of the distribution of optical scatterers and of the birefringent components.

  2. Video-rate dual polarization multispectral endoscopic imaging

    Science.gov (United States)

    Pigula, Anne; Clancy, Neil T.; Arya, Shobhit; Hanna, George B.; Elson, Daniel S.

    2015-03-01

    Cancerous and precancerous growths often exhibit changes in scattering, and therefore depolarization, as well as collagen breakdown, causing changes in birefringent effects. Simple difference of linear polarization imaging is unable to represent anisotropic effects like birefringence, and Mueller polarimetry is time-consuming and difficult to implement clinically. This work presents a dual-polarization endoscope to collect co- and cross-polarized images for each of two polarization states, and further incorporates narrow band detection to increase vascular contrast, particularly vascular remodeling present in diseased tissue, and provide depth sensitivity. The endoscope was shown to be sensitive to both isotropic and anisotropic materials in phantom and in vivo experiments.

  3. Polymeric optical waveguide devices exploiting special properties of polymer materials

    Science.gov (United States)

    Oh, Min-Cheol; Chu, Woo-Sung; Shin, Jin-Soo; Kim, Jun-Whee; Kim, Kyung-Jo; Seo, Jun-Kyu; Lee, Hak-Kyu; Noh, Young-Ouk; Lee, Hyung-Jong

    2016-03-01

    Optical polymer materials have many unique features that are unavailable in other inorganic optical materials. These include large thermo-optic effect with low thermal conductivity, index tunability by solution blending, structural diversity, freestanding flexibility, and controllable birefringence. Various functional integrated optic devices have been investigated by our group based on the specialties of fluorinated polymer material, which include extremely low crosstalk integrated optics, strain-controlled flexible waveguide tunable lasers, and birefringence-tuned polarization controllers. They have been demonstrated to have good performance, large fabrication tolerance, and high reliability, and they will be important building blocks for extending the application territory of polymeric optical waveguide devices.

  4. Magneto-optical phenomena in semiconductor superlattices

    International Nuclear Information System (INIS)

    The Faraday and birefringence effects due to infrared radiation in semiconductor superlattices under quantized magnetic field are investigated. It is shown that for non-degenerate electron gas in the one mini-band approximation the frequency behaviour of magneto-optical coefficients exhibit finite jumps at ω=ηωc±2Δ (ω is the frequency of electromagnetic radiation, ωc is the cyclotron frequency and Δ is half band width). The natural birefringence and dichroism in superlattices are also calculated. (author). 9 refs, 1 fig

  5. Magneto optical rotation in a GaAs Quantum Well Waveguide

    CERN Document Server

    Mortezapour, Ali; Mahmoudi, Mohammad

    2016-01-01

    The interaction of two orthogonally polarized beams and a four-level GaAs quantum well (QW) waveguide is investigated. It is shown that, by applying a static magnetic field normal to the propagation direction of the driving beams, the birefringence can be induced in the QW waveguide. Moreover, it is demonstrated that the dephasing rate between two ground states of the QW waveguide makes it a dichromatic medium and can also diminish the induced birefringence. Our results show how a large and complete magneto-optical rotation in the QW waveguide can be obtained via adjusting the intensity of the magnetic field and also the length of the QW waveguide.

  6. Orientation of the agarose gel matrix in pulsed electric fields.

    OpenAIRE

    Stellwagen, J; Stellwagen, N C

    1989-01-01

    The technique of transient electric birefringence was used to investigate the effect of pulsed electric fields on the orientation of the agarose gel matrix. Orientation of the gel was observed at all electric field strengths. Very slow, time-dependent effects were observed when pulses of 10-100 V/cm were applied to 1% gels for 0.5-2 seconds, indicating that domains of the matrix were being oriented by the electric field. The sign of the birefringence reversed when the direction of the applied...

  7. Reflective composite sheet design for LCD backlight recycling.

    Science.gov (United States)

    Kim, Taehyung; Kim, Kibeom; Lee, Eun Soo; Jeong, Won Young; Lim, Dae Young; Choi, Suk-Won

    2014-05-01

    We have designed a reflective composite sheet consisting of a birefringent polymer matrix and isolated isotropic or minimally birefringent fibers. The optical properties of the sheet have been investigated in terms of the width, spacing, and thickness of the individual fibers. Commercial software (FDTD Solution) was used to simulate the reflectance of the proposed sheet, and conventional processes such as cast-film extrusion in combination with solid-state drawing were used to manufacture the multilayer composite sheet. The measured and simulated reflectance spectra confirm the feasibility of employing the sheet as a reflective polarizer. PMID:24921815

  8. Tunable All-in-Fiber Waveplates Based on Negative Dielectric Liquid Crystal Photonic Bandgap Fibers

    DEFF Research Database (Denmark)

    Wei, Lei; Eskildsen, Lars; Weirich, Johannes;

    2008-01-01

    Tunable all-in-fiber waveplates based on negative dielectric liquid crystal photonic bandgap fibers are presented. The birefringence can be tuned electrically and thermally to work as a quarter-wave or a half-wave plate in the range 1520 nm-1580 nm.......Tunable all-in-fiber waveplates based on negative dielectric liquid crystal photonic bandgap fibers are presented. The birefringence can be tuned electrically and thermally to work as a quarter-wave or a half-wave plate in the range 1520 nm-1580 nm....

  9. High-energy Nd:Cr:GSGG lasers based on phase and polarization conjugated multiple-pass amplifiers

    Science.gov (United States)

    Jackel, Steven M.; Moshe, Inon; Kaufman, Alon; Lavi, Raphael; Lallouz, Raphael

    1997-07-01

    Lasers based on Nd:Cr:GSGG low-energy oscillator/high-energy multiple-pass amplifiers produced 1.7 J pulses in a M2 approximately equals 2 divergence beam at 2.4% electrical efficiency. Thermal lensing and birefringence correction were major factors driving the amplifier design. Essential components in achieving a moderate average power output were an intra-amplifier telescope to correct for lowest order thermal focusing, a phase conjugate mirror to correct for higher order thermal lensing aberrations, and a linear optics derived polarization conjugator to correct for birefringence.

  10. Selective properties of volume phase holograms in photorefractive crystals

    Science.gov (United States)

    Pencheva, T. G.; Petrov, M. P.; Stepanov, S. I.

    1982-01-01

    The paper deals with the selective properties (both angular and spectral) of volume phase holograms in birefringent and cubic optically active photorefractive crystals. It is shown that in birefringent crystals of LiNbO 3 type, the spectral selectivity of the grating depends remarkably on the type of diffraction (isotropic or anisotropic) and the polarization of the reconstructing plane light wave. In cubic optically active crystals the peculiarities of diffraction reveal themselves in a fine structure of differently polarized peaks in the Bragg maximum that can be easily observed, in particular in Bi 12SiO 20 samples with a thickness d ≈ 8 mm.

  11. Polarized Microscopy in Lesions With Altered Dermal Collagen.

    Science.gov (United States)

    Elbendary, Amira; Valdebran, Manuel; Parikh, Kruti; Elston, Dirk M

    2016-08-01

    Alterations in dermal collagen are noted in dermatofibroma, dermatofibrosarcoma protuberans, morphea, lichen sclerosus et atrophicus, hypertrophic scars, and keloids. The authors sought to determine whether variations in birefringence of collagen by polarized microscopy could be of help in diagnosing such conditions. Representative hematoxylin and eosin sections of 400 cases, including dermatofibroma, dermatofibrosarcoma protuberans, hypertrophic scars, keloid, morphea, and lichen sclerosus, were examined under polarized microscopy. Distinct patterns of birefringence of collagen for each disease were noted under polarized microscopy. This study highlights the use of polarized microscopy as adjunctive tool in differentiating different diseases with collagen alteration. PMID:26959692

  12. Design and analysis of optically pumped semiconductor VECSEL with ANECz optical control layer

    Institute of Scientific and Technical Information of China (English)

    Yuqi Zhou; Dapeng Zhao; Yajuan Li; Qingxin Yang

    2008-01-01

    Through the reversible isomerization of trans-cis-trans under the linear polarization light, the molecules of azo materials have the same tropism which is vertical to the polarization of light. This means that azo materials have photo-induced birefringence which is related to optical power and polarization angle of the light. Based on the photo-induced birefringence of azo materials, we design a new type of optically pumped semiconductor vertical external cavity surface emitting laser (OPS-VECSEL) which can control the polarization and frequency of the ejection laser. The functional molecules of azo materials are [3-azo- (4'nitro)]-(9-ethyl)-carbazole (ANECz).

  13. Polarization-dependent diffraction in all-dielectric, twisted-band structures

    Energy Technology Data Exchange (ETDEWEB)

    Kardaś, Tomasz M.; Jagodnicka, Anna; Wasylczyk, Piotr, E-mail: pwasylcz@fuw.edu.pl [Photonic Nanostructure Facility, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warszawa (Poland)

    2015-11-23

    We propose a concept for light polarization management: polarization-dependent diffraction in all-dielectric microstructures. Numerical simulations of light propagation show that with an appropriately configured array of twisted bands, such structures may exhibit zero birefringence and at the same time diffract two circular polarizations with different efficiencies. Non-birefringent structures as thin as 3 μm have a significant difference in diffraction efficiency for left- and right-hand circular polarizations. We identify the structural parameters of such twisted-band matrices for optimum performance as circular polarizers.

  14. A near-infrared zero-order achromatic retarder

    Indian Academy of Sciences (India)

    Arijit Saha; Kallol Bhattacharya; Ajoy Kumar Chakraborty

    2011-10-01

    Phase retarders normally show strong wavelength dependence. Achromatic retarders which exhibit nearly identical characteristics over a wide wavelength spectrum is used in polychromatic light. The present investigation deals with a technique to design and study the characteristics of an achromatic combination of birefringent plates in 800–2000 nm range. The retarder has been designed using calcite, crystalline quartz and ADP. The thicknesses of the plates are 19.38 m, 446.14 m and 12.57 m respectively. The new arrangement of three birefringent plates proposed has the promise of producing a zero-order quarter wave achromatic combination with fairly good accuracy.

  15. Polarization-dependent diffraction in all-dielectric, twisted-band structures

    Science.gov (United States)

    Kardaś, Tomasz M.; Jagodnicka, Anna; Wasylczyk, Piotr

    2015-11-01

    We propose a concept for light polarization management: polarization-dependent diffraction in all-dielectric microstructures. Numerical simulations of light propagation show that with an appropriately configured array of twisted bands, such structures may exhibit zero birefringence and at the same time diffract two circular polarizations with different efficiencies. Non-birefringent structures as thin as 3 μm have a significant difference in diffraction efficiency for left- and right-hand circular polarizations. We identify the structural parameters of such twisted-band matrices for optimum performance as circular polarizers.

  16. Polarization ray tracing in anisotropic optically active media. I. Algorithms

    International Nuclear Information System (INIS)

    Procedures for performing polarization ray tracing through birefringent media are presented in a form compatible with the standard methods of geometrical ray tracing. The birefringent materials treated include the following: anisotropic optically active materials such as quartz, non-optically active uniaxial materials such as calcite, and isotropic optically active materials such as mercury sulfide and organic liquids. Refraction and reflection algorithms are presented that compute both ray directions and wave directions. Methods for computing polarization modes, refractive indices, optical path lengths, and Fresnel transmission and reflection coefficients are also specified. A numerical example of these algorithms is given for analyzing the field of view of a quartz rotator. 37 refs., 3 figs

  17. The collagen structure of equine articular cartilage, characterized using polarization-sensitive optical coherence tomography

    International Nuclear Information System (INIS)

    Optical coherence tomography and polarization-sensitive optical coherence tomography images of equine articular cartilage are presented. Measurements were made on intact joint surfaces. Significant (e.g. x 2) variations in the intrinsic birefringence were found over spatial scales of a few millimetres, even on samples taken from young (18 month) animals that appeared visually homogeneous. A comparison of data obtained on a control tissue (equine flexor tendon) further suggests that significant variations in the orientation of the collagen fibres relative to the plane of the joint surface exist. Images of visually damaged cartilage tissue show characteristic features both in terms of the distribution of optical scatterers and of the birefringent components

  18. Physical models of polarization mode dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Menyuk, C.R.; Wai, P.K.A. [Univ. of Maryland, Baltimore, MD (United States)

    1995-12-31

    The effect of randomly varying birefringence on light propagation in optical fibers is studied theoretically in the parameter regime that will be used for long-distance communications. In this regime, the birefringence is large and varies very rapidly in comparison to the nonlinear and dispersive scale lengths. We determine the polarization mode dispersion, and we show that physically realistic models yield the same result for polarization mode dispersion as earlier heuristic models that were introduced by Poole. We also prove an ergodic theorem.

  19. Long-Range Surface Plasmons on Highly Anisotropic Dielectric Substrates

    Science.gov (United States)

    Gumen, L.; Nagaraj; Neogi, A.; Krokhin, A.

    We calculate the propagation length of surface plasmons in metal-dielectric structures with anisotropic substrates. We show that the Joule losses can be minimized by appropriate orientation of the optical axis of a birefringent substrate and that the favorable orientation of the axis depends on ω. A simple Kronig-Penney model for anisotropic plasmonic crystal is also proposed.

  20. Spontaneous Mathieu-Gauss mode oscillation in micro-grained Nd:YAG ceramic lasers with azimuth laser-diode pumping

    International Nuclear Information System (INIS)

    Mathieu-Gauss mode oscillations were observed in micro-grained isotropic Nd:YAG microchip ceramic lasers with azimuth laser diode pumping. The effect of fluorescence anisotropy or thermal birefringence on these pattern formations is discussed for several laser materials