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

    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...... and an 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. Birefringent Electroweak Textures

    CERN Document Server

    Thatcher, M J; Thatcher, Marcus J.; Morgan, Michael J.

    1999-01-01

    The behaviour of electromagnetic waves propagating through an electroweak homilia string network is examined. This string network is topologically stable as a cosmic texture, and is characterized by the spatial variation of the isospin rotation of the Higgs field. As a consequence the photon field couples to the intermediate vector bosons, producing a finite range electromagnetic field. It is found that the propagation speed of the photon depends on its polarization vector, whence an homilia string network acts as a birefringent medium. We estimate the birefringent scale for this texture and show that it depends on the frequency of the electromagnetic wave and the length scale of the homilia string network.

  4. 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.

  5. Quantum vacuum magnetic birefringence

    Energy Technology Data Exchange (ETDEWEB)

    Berceau, Paul; Battesti, Remy; Fouche, Mathilde; Frings, Paul; Nardone, Marc; Portugall, Oliver; Rikken, Geert L. J. A.; Rizzo, Carlo, E-mail: carlo.rizzo@lncmi.cnrs.fr [UPR 3228, CNRS-UPS-UJF-INSA, Laboratoire National des Champs Magnetiques Intenses (France)

    2012-05-15

    In this contribution to EXA2011 congress, we present the status of the BMV (Birefringence Magnetique du Vide) experiment which is based on the use of a state-of-the-art optical resonant cavity and high pulsed magnetic fields, and it is hosted by the Laboratoire National des Champs Magnetiques Intenses in Toulouse, France.

  6. 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.

  7. 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.

  8. 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.

  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 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.

  11. 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....

  12. Stress effects in twisted highly birefringent fibers

    Science.gov (United States)

    Wolinski, Tomasz R.

    1994-03-01

    Hydrostatic pressure and uniaxial longitudinal strain effects in twisted highly birefringent optical fibers have been investigated from the point of the Marcuse mode-coupling theory. The problem is analyzed in terms of local normal modes of the ideal fiber and in the limit of weak twist, where large linear birefringence dominates over twist effect, and therefore twist coupling between local modes is not effective. The authors present the results of birefringence measurements in highly birefringent bow-tie fibers influenced simultaneously by hydrostatic pressure up to 100 MPa and twisting the result for highly birefringent elliptical-core fibers influenced by uniaxial longitudinal strain up to 4000 (mu) (epsilon) and twisting effect. The birefringence measurement method is based on twist-induced effects and has been successfully applied in a stress environment. The experiment was conducted with a specially designed stress generating device that makes it possible to simultaneously generate various mechanical perturbations such as hydrostatic and radial pressure, axial strain and twist, allowing study of their influence on mode propagation in optical fibers. A comparison with theoretical results as well as with pervious experimental data on stress influence on the beat length parameter in highly birefringent fibers is also provided.

  13. 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.

  14. New constraints on gravity-induced birefringence

    Science.gov (United States)

    Solanki, Sami K.; Haugan, Mark P.

    1996-01-01

    A wide class of gravitation theories predicts gravity-induced birefringence. For Moffat's NGT, the prototypical theory of this type, Gabriel, Haugan, Mann, and Palmer used the predicted gravitational birefringence and observations of solar polarization to constrain the Sun's nonsymmetric charge lsolar. We improve on this constraint by making use of improved knowledge of the solar source of polarization and of a refined analysis procedure. We obtain l2solar< (305 km)2.

  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. Jones birefringence in twisted single-mode optical fibers.

    Science.gov (United States)

    Tentori, Diana; Garcia-Weidner, A

    2013-12-30

    In this work we analyze the birefringence matrix developed for a twisted fiber in order to identify the basic optical effects that define its birefringence. The study was performed using differential Jones calculus. The resultant differential matrix showed three independent types of birefringence: circular, linear at 0 degrees and linear at 45 degrees (Jones birefringence). We applied this birefringence matrix to the description of the output state of polarization measured for three commercial fibers that due to its higher rigidity present stronger birefringence changes when twisted. The torsion applied to the erbium-doped fiber samples varied from 0 to 1440 degrees. PMID:24514769

  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. 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...

  19. 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 $\

  20. 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 $\\chi < 10^{-3}$.

  1. Birefringence insensitive optical coherence domain reflectometry system

    Science.gov (United States)

    Everett, Matthew J.; Davis, Joseph G.

    2002-01-01

    A birefringence insensitive fiber optic optical coherence domain reflectometry (OCDR) system is provided containing non-polarization maintaining (non-PM) fiber in the sample arm and the reference arm without suffering from signal degradation caused by birefringence. The use of non-PM fiber significantly reduces the cost of the OCDR system and provides a disposable or multiplexed section of the sample arm. The dispersion in the reference arm and sample arm of the OCDR system are matched to achieve high resolution imaging. This system is useful in medical applications or for non-medical in situ probes. The disposable section of non-PM fiber in the sample arm can be conveniently replaced when contaminated by a sample or a patient.

  2. Vacuum Birefringence as a Vacuum Emission Process

    CERN Document Server

    Karbstein, Felix

    2015-01-01

    We argue that the phenomenon of vacuum birefringence in strong inhomogeneous electromagnetic fields can be most efficiently analyzed in terms of a vacuum emission process. In this contribution, we exemplarily stick to the case of vacuum birefringence in a stationary perpendicularly directed, purely magnetic background field extending over a finite spatial extent. Similar field configurations are realized in the BMV and PVLAS experiments. We demonstrate that we can reproduce the conventional constant field result. Our focus is on effects which arise when the probe photons originate in the field free region, are directed towards the magnetic field region, and detected well after the interaction with the magnetic field has taken place, again at zero field.

  3. 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.

  4. Magnetic Linear Birefringence Measurements Using Pulsed Fields

    CERN Document Server

    Berceau, Paul; Battesti, Remy; Rizzo, Carlo

    2011-01-01

    In this paper we present the accomplishment of the further step towards the vacuum magnetic birefringence measurement based on pulsed fields. After describing our BMV experiment, we report the calibration of our apparatus with nitrogen gas and we discuss the precision of our measurement giving a detailed error budget. Our best present vacuum sensitivity is 2.1x 10^-19 T^-2 per 5 ms magnetic pulse. We finally discuss the perspectives to reach our final goal.

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

    CERN Document Server

    Della Valle, F; Ejlli, A; Gastaldi, U; Messineo, G; Zavattini, G; Pengo, R; Ruoso, G

    2015-01-01

    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 the 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.

  6. 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.)

  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. Transfer matrix for treating stratified media including birefringent crystals.

    Science.gov (United States)

    Essinger-Hileman, Thomas

    2013-01-10

    Birefringent crystals are extensively used to manipulate polarized light. The generalized transfer matrix developed allows efficient calculation of the full polarization state of light transmitted through and reflected by a stack of arbitrarily many discrete layers of isotropic and birefringent materials at any frequency and angle of incidence. The matrix of a uniaxial birefringent crystal with arbitrary rotation is calculated, along with its reduction to the matrix of an isotropic medium. This method is of great practical importance where tight control of systematic effects is needed in optical systems employing birefringent crystals, one example being wave plates used by cosmic microwave background polarimetry with wide field-of-view telescopes.

  9. 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...

  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 non-polarizing thin film design

    Institute of Scientific and Technical Information of China (English)

    QI; Hongji; HONG; Ruijin; HE; Hongbo; SHAO; Jianda; FAN; Zh

    2005-01-01

    In this paper, 2×2 characteristic matrices of uniaxially anisotropic thin film for extraordinary and ordinary wave are deduced at oblique incidence. Furthermore, the reflectance and transmittance of thin films are calculated separately for two polarizations, which provide a new concept for designing non-polarizing thin films at oblique incidence. Besides, using the multilayer birefringent thin films, non-polarizing designs, such as beam splitter thin film at single wavelength, edge filter and antireflection thin film over visible spectral region are obtained at oblique incidence.

  12. 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.

  13. 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...

  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 in pseudo-Finsler spacetimes

    CERN Document Server

    Skakala, Jozef

    2008-01-01

    Based on the analogue spacetime programme, and many other ideas currently mooted in "quantum gravity", there is considerable ongoing speculation that the usual pseudo-Riemannian (Lorentzian) manifolds of general relativity might eventually be modified at short distances. Two specific modifications that are often advocated are the adoption of Finsler geometries (or more specifically, pseudo-Finsler spacetimes) and the possibility of birefringence (or more generally, multi-refringence). We have investigated the possibility of whether it is possible to usefully and cleanly deal with these two possibilities simultaneously. That is, given two (or more) "signal cones": Is it possible to naturally and intuitively construct a "unified" pseudo-Finsler spacetime such that the pseudo-Finsler metric is null on these "signal cones", but has no other zeros or singularities? Our results are much less encouraging than we had originally hoped, and suggest that while pseudo-Finsler spacetimes are certainly useful constructs, i...

  17. 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.

  18. 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.

  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. 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...

  1. 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.

  2. 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.

  3. Ultrahigh Birefringent Photonic Crystal Fiber with Ultralow Confinement Loss

    Directory of Open Access Journals (Sweden)

    Jyoti,

    2014-06-01

    Full Text Available A photonic crystal fiber (PCF with circular air holes in the fiber cladding and elliptical air holes in the fiber core is proposed. According to calculation, both ultrahigh birefringence (larger than 0.01 and ultralow confinement loss (less than 0.001dB/km can be achieved simultaneously over a large wavelength range for a PCF with only four rings of circular air holes in the fiber cladding. The confinement loss in this PCF can be effectively reduced while the birefringence almost remains the same. The proposed design of the PCF is a solution to the tradeoff between the birefringence and the confinement loss for the originally reported highly birefringent elliptical-hole PCF. Moreover, an approach to modify the effective index of fiber core is also suggested in this letter.

  4. 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 ...

  5. 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.

  6. 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...

  7. 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...

  8. 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...

  9. 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.

  10. Quantifying strain birefringence halos around inclusions in diamond

    Science.gov (United States)

    Howell, D.; Wood, I. G.; Dobson, D. P.; Jones, A. P.; Nasdala, L.; Harris, J. W.

    2010-11-01

    The pressure and temperature conditions of formation of natural diamond can be estimated by measuring the residual stress that an inclusion remains under within a diamond. Raman spectroscopy has been the most commonly used technique for determining this stress by utilising pressure-sensitive peak shifts in the Raman spectrum of both the inclusion and the diamond host. Here, we present a new approach to measure the residual stress using quantitative analysis of the birefringence induced in the diamond. As the analysis of stress-induced birefringence is very different from that of normal birefringence, an analytical model is developed that relates the spherical inclusion size, R i, host diamond thickness, L, and measured value of birefringence at the edge of the inclusion, Updelta n(R_{text{i}} )_{text{av}} , to the peak value of birefringence that has been encountered; to first order Updelta n_{text{pk}} = (3/4)(L/R_{text{i}} ) Updelta n(R_{text{i}} )_{text{av}} . From this birefringence, the remnant pressure ( P i) can be calculated using the photoelastic relationship Updelta n_{text{pk}} = - (3/4)n3 q_{text{iso}} P_{text{i}} , where q iso is a piezo-optical coefficient, which can be assumed to be independent of crystallographic orientation, and n is the refractive index of the diamond. This model has been used in combination with quantitative birefringence analysis with a MetriPol system and compared to the results from both Raman point and 2D mapping analysis for a garnet inclusion in a diamond from the Udachnaya mine (Russia) and coesite inclusions in a diamond from the Finsch mine (South Africa). The birefringence model and analysis gave a remnant pressure of 0.53 ± 0.01 GPa for the garnet inclusion, from which a source pressure was calculated as 5.7 GPa at 1,175°C (temperature obtained from IR analysis of the diamond host). The Raman techniques could not be applied quantitatively to this sample to support the birefringence model; they were, however, applied

  11. 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.

  12. Birefringence of single and bundled microtubules.

    Science.gov (United States)

    Oldenbourg, R; Salmon, E D; Tran, P T

    1998-01-01

    We have measured the birefringence of microtubules (MTs) and of MT-based macromolecular assemblies in vitro and in living cells by using the new Pol-Scope. A single microtubule in aqueous suspension and imaged with a numerical aperture of 1.4 had a peak retardance of 0.07 nm. The peak retardance of a small bundle increased linearly with the number of MTs in the bundle. Axonemes (prepared from sea urchin sperm) had a peak retardance 20 times higher than that of single MTs, in accordance with the nine doublets and two singlets arrangement of parallel MTs in the axoneme. Measured filament retardance decreased when the filament was defocused or the numerical aperture of the imaging system was decreased. However, the retardance "area," which we defined as the image retardance integrated along a line perpendicular to the filament axis, proved to be independent of focus and of numerical aperture. These results are in good agreement with a theory that we developed for measuring retardances with imaging optics. Our theoretical concept is based on Wiener's theory of mixed dielectrics, which is well established for nonimaging applications. We extend its use to imaging systems by considering the coherence region defined by the optical set-up. Light scattered from within that region interferes coherently in the image point. The presence of a filament in the coherence region leads to a polarization dependent scattering cross section and to a finite retardance measured in the image point. Similar to resolution measurements, the linear dimension of the coherence region for retardance measurements is on the order lambda/(2 NA), where lambda is the wavelength of light and NA is the numerical aperture of the illumination and imaging lenses. PMID:9449366

  13. Estimation of the Birefringence Change in Crystals Induced by Gravitation Field

    OpenAIRE

    Vlokh R.; Kostyrko M.

    2007-01-01

    The effect of gravitation field of spherically symmetric mass on the birefringent properties of crystals has been analysed. It has been shown that the gravitation field with spherical symmetry can lead to a change of birefringence in anisotropic media.

  14. Vacuum magnetic linear birefringence using pulsed fields: the BMV experiment

    CERN Document Server

    Cadène, A; Fouché, M; Battesti, R; Rizzo, C

    2013-01-01

    In this letter we present the measurement of the vacuum magnetic birefringence obtained using the first generation setup of the BMV experiment. In particular, we detail our procedure of data acquisition and our analysis which takes into account the symmetry properties of raw data with respect to the orientation of the magnetic field and the sign of the cavity birefringence. Our current value of vacuum magnetic linear birefringence k_CM was obtained with about 100 magnetic pulses and a maximum field of 6.5 T. We get k_CM = (-7.4 \\pm 8.7).10^{-21} T^{-2} at 3 sigma confidence level. Our result is a clear validation of our innovative experimental method.

  15. 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.

  16. 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

  17. 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

  18. Inverse Relaxation of Photoinduced Birefringence in a Liquid-Crystalline Azobenzene Side-Chain Polymer

    Institute of Scientific and Technical Information of China (English)

    PAN Xu; WANG Chang-Shun; ZHANG Xiao-Qiang

    2008-01-01

    Photoinduced birefringence in a liquid-crystalline azobenzene side-chain polymer is investigated. It is observed that the birefringence does not show any decay but increases after switching off the pump light at room temperature. The magnitude of the birefringence relaxation is found to depend on the exposure dose of the pump light.A discussion about the mechanism of the inverse relaxation of birefringence is presented.

  19. Tightly Focusing of Circularly Polarized Vortex Beams through a Uniaxial Birefringent Crystal

    Institute of Scientific and Technical Information of China (English)

    RAO Lian-Zhou; WANG Zong-Chi; ZHENG Xiao-Xia

    2008-01-01

    Under the approximation of small birefringence, the properties of circalarly polarized vortex beams tightly focused through a uniaxial birefringent crystal are studied. With the proper combination of the topological charge and the birefringence, the small focus, the small bottle beam and the inverse c-shaped intensity profile can be obtained.The effects of the focal shift and the Strehl ratio on the birefringence are analysed. A relation between angular momentum (included spin and orbital) and topological Pancharatnam charge is also presented.

  20. 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

  1. 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.

  2. A Simple Birefringent Terahertz Waveguide Based on Polymer Elliptical Tube

    Institute of Scientific and Technical Information of China (English)

    WANG Jing-Li; YAO Jian-Quan; CHEN He-Ming; LI Zhong-Yang

    2011-01-01

    We propose a simple birefringent terahertz (THz) waveguide which is a polymer elliptical tube with a cross section of elliptical ring structure. It can be achieved by stretching a normal circular-tube in one direction. Simulations based on the full-vector finite element method (FEM) show that this kind of waveguides exhibits high birefringence on a level of 10-2 over a wide THz frequency range. Moreover, as a majority of modal power is trapped in the air core inside the polymer elliptical tube, the THz waveguide guiding loss caused by material absorption can be reduced effectively.

  3. 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.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    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...

  5. 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.

  6. Highly Birefringent Photonic Crystal Fibers BUsing Asymmetric Core Design

    Institute of Scientific and Technical Information of China (English)

    Zhao Chun-Liu; Lu Chao; Yan Min; Wang Xiaoyan; Lou Junjun; Li Qin; Zhou Xiaoqun; Cai Qing; P.R.Chaudhuri

    2003-01-01

    We demonstrate a highly birefringent photonic crystal fiber by utilizing the asymmetric core design. Based on spectral measurements of the polarization mode interfering, we estimate that the fiber has a beat length of about 0.33 mm at 1545 nm.

  7. Highly Birefringent Photonic Crystal Fibers B Using Asymmetric Core Design

    Institute of Scientific and Technical Information of China (English)

    Zhao; Chun-Liu; Lu; Chao; Yan; Min; Wane; Xiaoyan; Lou; Junjun; Li; Qin; Zhou; Xiaoqun

    2003-01-01

    We demonstrate a highly birefringent photonic crystal fiber by utilizing the asymmetric core design. Based on spectral measurements of the polarization mode interfering, we estimate that the fiber has a beat length of about 0.33 mm at 1545 nm.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    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...

  9. 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.

  10. Giant Birefringence of Lithium Niobate Crystals in the Terahertz Region

    Institute of Scientific and Technical Information of China (English)

    SUN Yi-Min; MAO Zong-Liang; HOU Bi-Hui; LIU Guo-Qing; WANG Li

    2007-01-01

    Terahertz time-domain spectroscopy (THz-TDS) is used to study the spectral response of lithium niobate crystals (LiNbO3) in the far infrared region. The optical constants are derived from the measured complex refractive index.A giant birefringence is observed in this material, and the average refractive-index difference between the ordinary wave and the extraordinary wave, no - ne, can reach up to about 1.6. Such a large birefringence is attributed to the different phonon modes of A1 (z) and E(x, y). This unusual property makes LiNbO3 a promising material to be used as a functional material in the terahertz region, e.g. Employed as wave-plates and polarization separators.

  11. Fourier polarimetry of the birefringence distribution of myocardium tissue

    Science.gov (United States)

    Ushenko, O. G.; Dubolazov, O. V.; Ushenko, V. O.; Gorsky, M. P.; Soltys, I. V.; Olar, O. V.

    2015-11-01

    The results of optical modeling of biological tissues polycrystalline multilayer networks have been presented. Algorithms of reconstruction of parameter distributions were determined that describe the linear and circular birefringence. For the separation of the manifestations of these mechanisms we propose a method of space-frequency filtering. Criteria for differentiation of causes of death due to coronary heart disease (CHD) and acute coronary insufficiency (ACI) were found.

  12. 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...

  13. Threshold of polarization instability for solitons in birefringent fibers

    Energy Technology Data Exchange (ETDEWEB)

    Nesterov, L.; Kondrat`ev, Y. [S.I. Vavilov State Optical Inst., St. Petersburg (Russian Federation). Scientific-Research and Technological Inst. of Optical Materials Science; Nolan, D. [Corning Inc., NY (United States)

    1994-12-31

    The threshold of polarization instability for solitons in birefringent fibers has been calculated analytically. The problem was studied when the polarization state of the soliton is oriented along one principal axis and the polarization state of the perturbation is oriented along the other. The instability threshold corresponds to the soliton field intensity which causes the exponential growing of the perturbation. The authors have shown for the first time that this problem can be solved exactly under the assumption that the influence of group velocity difference between the soliton and the perturbation on the instability threshold is negligible. Analytical expressions has been obtained for the threshold of the soliton instability and its duration. The polarization instability increment near threshold has also been calculated. It was shown that obtained analytical expressions are valid under a wide range of birefringent values. On the basis of these expressions, the general analysis of soliton propagation in birefringent fibers has been made and estimations of the instability threshold have been made. The results of this work can be used for the study of ultra-fast all optical switching as well as for the analyses of soliton propagation in optical fibers.

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Design of anisotropic reflector with birefringent thin films

    Institute of Scientific and Technical Information of China (English)

    Jianguo Wang; Kui Yi; Jianda Shao; Zhengxiu Fan

    2005-01-01

    A novel design for dielectric anisotropic mirrors with birefringent thin films for normal incidence is presented. This mirror consists of a stack of quarter-wave biaxial layers. The biaxial anisotropic layers can be fabricated by oblique deposition. The reflectance is different for two linear polarizations of light incidence on the mirrors. As a numerical example, the design is carried out on glass with TiO2 and ZrO2. These thin films could be applied to anisotropic reflective devices for lasers.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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...

  5. 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.

  6. 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

  7. Measuring the Length Distribution of a Fibril System: a Flow Birefringence Technique applied to Amyloid Fibrils

    NARCIS (Netherlands)

    Rogers, S.S.; Venema, P.; Sagis, L.M.C.; Linden, van der E.; Donald, A.M.

    2005-01-01

    Relaxation of flow birefringence can give a direct measure of the rotational diffusion of rodlike objects in solution. With a suitable model of the rotational diffusivity, a length distribution can be sought by fitting the decay curve. We have measured the flow birefringence decay from solutions of

  8. 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...

  9. Birefringence of Muscovite Mica Plate Temperature Effect in the Ultraviolet and Visible Spectrum

    CERN Document Server

    Zhang, Xu; Qi, Limei; Zhang, Xia; Hao, Dianzhong

    2014-01-01

    We developed a method to measure the phase retardation and birefringence of muscovite mica plate in the temperature range of 223K to 358K within the spectrum of 300 to 700 nm. The phase retardation data is gained through the standard transmission ellipsometry using spectroscopic ellipsometer. With the phase retardation and thickness of the mica plate we can calculate its birefringence dispersion. Our results give abundant phase retardation and birefringence data of muscovite mica in the ultraviolet and visible spectrum from 223K to 358K. From the experimental data, the phase retardation and birefringence will drop down at the fixed wavelength when the temperature rises. The accuracy of the birefringence of mica plate is better than 3.5e-5.

  10. 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.

  11. Birefringence-Directed Raman Selection Rules in 2D Black Phosphorus Crystals.

    Science.gov (United States)

    Mao, Nannan; Wu, Juanxia; Han, Bowen; Lin, Jingjing; Tong, Lianming; Zhang, Jin

    2016-05-01

    The incident and scattered light engaged in the Raman scattering process of low symmetry crystals always suffer from the birefringence-induced depolarization. Therefore, for anisotropic crystals, the classical Raman selection rules should be corrected by taking the birefringence effect into consideration. The appearance of the 2D anisotropic materials provides an excellent platform to explore the birefringence-directed Raman selection rules, due to its controllable thickness at the nanoscale that greatly simplifies the situation comparing with bulk materials. Herein, a theoretical and experimental investigation on the birefringence-directed Raman selection rules in the anisotropic black phosphorus (BP) crystals is presented. The abnormal angle-dependent polarized Raman scattering of the Ag modes in thin BP crystal, which deviates from the normal Raman selection rules, is successfully interpreted by the theoretical model based on birefringence. It is further confirmed by the examination of different Raman modes using different laser lines and BP samples of different thicknesses.

  12. Numerical and experimental analysis of the birefringence of large air fraction slightly unsymmetrical holey fibres

    CERN Document Server

    Labonté, Laurent; Roy, Philippe; Faouzi, Bahloul; Mourad, Zghal

    2010-01-01

    Careful numerical computations show that very slight geometrical imperfections of the cross-section of actual large air-fraction holey fibres (d/{\\Lambda} > 0.6) may induce surprisingly high birefringence, corresponding to beat lengths as short as few millimeters. The spectral variations of this birefringence obeys laws similar to those of elliptical core Hi-Bi holey fibres with low air-fraction. For all the tested fibres, the group birefringence numerically deduced from the only shape birefringence is in good agreement with the measured one that does not varies when strongly heating the fibres. These computations and measurements show that the contribution of possible inner stress to the birefringence is negligible.

  13. 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.

  14. 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.

  15. 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 ...

  16. 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.

  17. 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.

  18. Propagation of Optical Pulses in Polarization Maintaining Highly Birefringent Fibers

    Science.gov (United States)

    Leiva, Ariel; Olivares, Ricardo

    2008-04-01

    The propagation of Gaussian optical pulses through optical PM-HiBi (Polarization Maintaining Highly Birefringent) fibers is analyzed and simulated. Based upon a model of propagation as described by Marcuse, et al., [1] and Sunnerud, et al., [2], and the use of PMD (Polarization Mode Dispersion) compensators and emulators used by Kogelnik, et al. [2], [3] and Lima, et al. [4], we construct a simple model that allows graphical representation of the distortion experienced by optical pulses when propagating in a PM-HiBi fiber for different initial polarizations. The results of our analysis have the benefit of being identical to the more elaborate models of [1], [2], while also providing the additional advantage of simple graphical representation.

  19. 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.

  20. 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.

  1. 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.

  2. 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)

  3. Quantification of fatigue state in CFRP using ultrasonic birefringence

    Science.gov (United States)

    Fey, Peter; Kreutzbruck, Marc

    2016-02-01

    Fiber reinforced plastics are widely used in high performance application areas such as aerospace, automotive and wind energy. They are preferred over classic materials such as metals because of their superior weight to stiffness ratio. When subjected to cyclic or static loading, micro-cracks develop and hence their stiffness degrades. The rate of stiffness degradation depends on the angle between the fibers and the applied load. Because commonly used fiber reinforced composites consist of multiple layers with different fiber directions to cope with different loads applied to the material, the stiffness degradation has to be analyzed for each fiber direction. One method to analyze the stiffness degradation in fiber reinforced materials is ultrasonic birefringence. A birefringent effect as it is known for light in optics is also observed for ultrasonic shear waves in fiber reinforced composites because of their elastic anisotropy. The role of the polarization dependent refractive index is taken by the propagation velocity of shear waves. If polarized parallel to the fiber direction they have a higher velocity than polarized perpendicularly to the fiber direction. The velocity depends on shear stiffness of the material. A model to predict the behavior of shear waves in multi-ply layups has been presented previously by Rheinfurth, Fey, Allinger and Busse[1]. That model was used to manually match measured and simulated phase and amplitude curves for waves that traversed the material under different angles between polarization direction of the emitting transducer and fiber direction in the first ply. Here another mode of interpreting the simulated results is used: amplitude and phase for each transducer orientation angle are combined to a complex number. Displaying them in the complex plane for one half rotation of the transducer yields an ellipse. Semi axis lengths and orientation can be obtained by Fourier transform and are used to compare the simulation to measured

  4. Birefringence in anisotropic optical fibres studied by polarised light Brillouin reflectometry

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A S; Burdin, V V; Konstantinov, Yu A; Petukhov, A S; Drozdov, I R; Kuz' minykh, Ya S; Besprozvannykh, V G [Perm National Research Polytechnic University (PNRPU), Perm (Russian Federation)

    2015-01-31

    Modal birefringence (the difference between the effective refractive indices of orthogonal polarisation modes) is one of the key parameters of anisotropic single-mode fibres, characterising their ability to preserve a linearly polarised state of input light. This parameter is commonly measured using short pieces of fibre, but such procedures are destructive and allow the birefringence to be determined only at the ends of long fibres. In this study, polarised light Brillouin reflectometry is used to assess birefringence uniformity throughout the length of an anisotropic fibre. (optical fibres)

  5. Dielectric relaxation and birefringence study of 7.O5O.7 dimeric liquid crystal compound

    Science.gov (United States)

    Bhattacharjee, Debanjan; Paul-Choudhury, Sandip; Alapati, Parameswara Rao; Bhattacharjee, Ayon

    2016-05-01

    Measurement of dielectric relaxation and birefringence phenomenon of dimeric liquid crystal compound with the dependence of temperature was reported in this paper. Homogeneous (HG) and homeotropic (HT) alignment of the cell are introduced to investigate the dielectric relaxation, activation energy and birefringence. Cole-Cole plots analyzed the dielectric relaxation of the dimeric compound. The observed Cole-Cole plots were semi-circular, and the relaxation mechanism obeys the non-Debye type of relaxation behaviour. Slater's perturbation equations have been used to analysis the activation energy of the compound. The birefringence of the compound has positively anisotropy and thin prism mechanism was used to study the anisotropy of the compound.

  6. Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber.

    Science.gov (United States)

    Tchahame, Joël Cabrel; Beugnot, Jean-Charles; Kudlinski, Alexandre; Sylvestre, Thibaut

    2015-09-15

    We investigate the stimulated Brillouin scattering (SBS) in a long tapered birefringent solid-core photonic crystal fiber (PCF) and compare our results with a similar but untapered PCF. It is shown that the taper generates a broadband and multipeaked Brillouin spectrum, while significantly increasing the threshold power. Furthermore, we observe that the strong fiber birefringence gives rise to a frequency shift of the Brillouin spectrum which increases along the fiber. Numerical simulations are also presented to account for the taper effect and the birefringence. Our findings open a new means to control or inhibit the SBS by tapering photonic crystal fibers. PMID:26371916

  7. 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.

  8. A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields

    Energy Technology Data Exchange (ETDEWEB)

    Zavattini, G.; Ejlli, A. [Universita di Ferrara, Dipt. di Fisica e Scienze della Terra (Italy); INFN, Sezione di Ferrara (Italy); Della Valle, F. [Universita di Trieste, Dipt. di Fisica, Trieste (Italy); INFN, Sezione di Trieste, TS (Italy); Ruoso, G. [INFN, Lab. Nazionali di Legnaro (Italy)

    2016-05-15

    A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the measurement of the magnetic birefringence of vacuum with the HERA superconducting magnets in the ALPS-II configuration is discussed. (orig.)

  9. 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.

  10. 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))

  11. Quantitative Assessment of Birefringent Skin Structures in Scattered Light Confocal Imaging Using Radially Polarized Light

    Directory of Open Access Journals (Sweden)

    Natallia Eduarda Uzunbajakava

    2013-09-01

    Full Text Available The polarization characteristics of birefringent tissues could be only partially obtained using linearly polarized light in polarization sensitive optical imaging. Here we analyze the change in polarization of backscattered light from birefringent structures versus the orientations of the incident polarizations using linearly, circularly and radially polarized light in a cross-polarized confocal microscope. A spatially variable retardation plate composed of eight sectors of λ/2 wave plates was used to transform linearly polarized light into a radially polarized light. Based on the experimental data obtained from ex-vivo measurements on human scalp hairs and in-vivo measurements on hair and skin, we exemplify that the underestimation of the birefringence content resulting from the orientation related effects associated with the use of linearly polarized light for imaging tissues containing wavy birefringent structures could be minimized by using radially polarized light.

  12. 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.

  13. Sensitivity of Bragg gratings in birefringent optical fiber to transverse compression between conforming materials.

    Science.gov (United States)

    Dennison, Christopher R; Wild, Peter M

    2010-04-20

    A theoretical and experimental investigation of the transverse load sensitivity of Bragg gratings in birefringent fibers to conforming contact is presented. A plane elasticity model is used to predict the contact dimensions between a conforming material and optical fiber and the principal stresses, indicating birefringence, created as a result of this contact. The transverse load sensitivity of commercially available birefringent fiber is experimentally measured for two cases of conforming contact. Theoretical and experimental results show that birefringent optical fiber can be used to make modulus-independent measurements of contact load. Therefore, Bragg gratings could be applied to conforming contact load measurements while avoiding some of the complications associated with existing contact sensors: specifically, the necessity to precalibrate by using materials with mechanical properties identical to those found in situ.

  14. A polarisation modulation scheme for measuring vacuum magnetic birefringence with static fields

    CERN Document Server

    Zavattini, G; Ejlli, A; Ruoso, G

    2016-01-01

    A novel polarisation modulation scheme for polarimeters based on Fabry-Perot cavities is presented. The application to the proposed HERA-X experiment aiming to measuring the magnetic birefringence of vacuum with the HERA superconducting magnets is discussed.

  15. 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.

  16. 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.

  17. 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 ...

  18. Approach for fast numerical propagation of uniformly polarized random electromagnetic fields in dispersive linearly birefringent systems.

    Science.gov (United States)

    Makowski, Piotr L; Domanski, Andrzej W

    2013-09-01

    An efficient simulation technique is proposed for computing propagation of uniformly polarized statistically stationary fields in linear nonimage-forming systems that includes dispersion of linear birefringence to all orders. The method is based on the discrete-time Fourier transformation of modified frequency profiles of the spectral Stokes parameters. It works under the condition that all (linearly) birefringent sections present in the system are described by the same phase birefringence dispersion curve, being a monotonic function of the optical frequency within the bandwidth of the light. We demonstrate the technique as a supplement for the Mueller-Stokes matrix formalism extended to any uniformly polarized polychromatic illumination. Accuracy of its numerical implementation has been verified by using parameters of a Lyot depolarizer made of a highly birefringent and dispersive monomode photonic crystal fiber.

  19. Band structure and Bloch states in birefringent 1D magnetophotonic crystals: An analytical approach

    CERN Document Server

    Lévy, M; Levy, Miguel; Jalali, Amir A

    2007-01-01

    An analytical formulation for the band structure and Bloch modes in elliptically birefringent magnetophotonic crystals is presented. The model incorporates both the effects of gyrotropy and linear birefringence generally present in magneto-optic thin film devices. Full analytical expressions are obtained for the dispersion relation and Bloch modes in a layered stack photonic crystal and their properties are analyzed. It is shown that other models recently discussed in the literature are contained as special limiting cases of the formulation presented herein.

  20. 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.

  1. 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

  2. Light-induced rotations of chiral birefringent microparticles in optical tweezers

    Science.gov (United States)

    Donato, M. G.; Mazzulla, A.; Pagliusi, P.; Magazzù, A.; Hernandez, R. J.; Provenzano, C.; Gucciardi, P. G.; Maragò, O. M.; Cipparrone, G.

    2016-09-01

    We study the rotational dynamics of solid chiral and birefringent microparticles induced by elliptically polarized laser light in optical tweezers. We find that both reflection of left circularly polarized light and residual linear retardance affect the particle dynamics. The degree of ellipticity of laser light needed to induce rotations is found. The experimental results are compared with analytical calculations of the transfer of angular moment from elliptically polarized light to chiral birefringent particles.

  3. 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

  4. 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.

  5. 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.)

  6. 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.

  7. Influence of Photosensitive Group Concentration on Birefringence Induced in Benzaldehyde Polymers

    Science.gov (United States)

    Mahilny, U. V.; Stankevich, A. I.; Trofimova, A. V.

    2014-01-01

    Induction of optical anisotropy in benzaldehyde polymer layers by linearly polarized UV radiation was investigated experimentally. Negative dichroism in absorption spectra and strong negative birefringence (-2 · 10-3) were related to the presence of an oriented ensemble of residual benzaldehyde groups. The thermal stability of photoinduced birefringence at high photosensitive group concentration was associated with a high density of photocross-links formed between macromolecules.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. Ultrasonic light diffraction in optically isotropic media with induced birefringence

    Science.gov (United States)

    Blomme, Erik; Sliwinski, Antoni

    2001-11-01

    Optically isotropic media which are susceptible to acoustically induced birefringence can be used as acousto- optic polarization converters. A comparative study between fused silica and dense flint shows that at normal light incidence 52% of the light can be converted from linear to circular in the case of fused silica and only 20% in the case of dense flint. In each case the conversion appears at moderate sound amplitudes and at frequencies which are typical for the intermediate regime of diffraction. Applying oblique light incidence, most interesting effects can be obtained with fused silica at high sound frequencies which are typical for the Bragg regime of diffraction and in the neighborhood of the Bragg angle. The possibility is shown to use an AO cell fabricated of fused silica as a laser-beam splitter, converting a linearly polarized beam of light partially into a circularly polarized beam and a linearly polarized beam, the light intensity of the two beams being equal. In addition, it is seen that the temporal light intensity modulations which can be observed in the near field of the light diffracted under these specific conditions, can be understood from the polarization changes taking place.

  16. Properties of monomeric paramyosin using a transient electric birefringence techniques.

    Science.gov (United States)

    DeLaney, D; Krause, S

    1976-01-01

    Paramyosin samples obtained from the chowder clam, Mercenaria mercenaria, by different extraction techniques were studied using transient electric birefringence techniques. The protein remain monomeric (unaggregated) in 1 mM buffer solution at pH 3.1 to 3.8 and near pH 10. At pH 3.2, the molecules obtained by different extraction techniques exhibit rotational diffusion constants that indicate a 5% difference in length between them, with the probable native form of paramyosin being the longer species. This difference in rotational diffusion constant disappears at higher pH, and, in addition, a large difference in dipole moment between the molecules observed at pH 3.2 also disappears at high pH. These results are used to hypothesize that the rodlike native paramyosin molecules have one or two partly flexible portions on their ends; at one end of each molecule this portion probably contains excess basic amino acids which are charged at low pH to account for the higher dipole moment of this form of paramyosin at these low pH values. At pH 3.2, these portions of the macromolecule are not flexible and act as stiff parts of the rodlike molecules, but they gradually become flexible at higher pH. Possible mechanisms for this change in flexibility are discussed.

  17. 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.

  18. 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.

  19. Design and analysis of surface plasmon resonance sensor based on high-birefringent microstructured optical fiber

    Science.gov (United States)

    Zhang, Nancy Meng Ying; Juan Juan Hu, Dora; Shum, Perry Ping; Wu, Zhifang; Li, Kaiwei; Huang, Tianye; Wei, Lei

    2016-06-01

    Optical fiber based surface plasmon resonance (SPR) sensors are favored by their high sensitivity, compactness, remote and in situ sensing capabilities. Microstructured optical fibers (MOFs) possess microfluidic channels extended along the entire length right next to the fiber core, thereby enabling the infiltrated biochemical analyte to access the evanescent field of guided light. Since SPR can only be excited by the polarization vertical to metal surface, external perturbation could induce the polarization crosstalk in fiber core, thus leading to the instability of sensor output. Therefore for the first time we analyze how the large birefringence suppresses the impact of polarization crosstalk. We propose a high-birefringent MOF based SPR sensor with birefringence larger than 4 × 10‑4 as well as easy infiltration of microfluidic analyte, while maintaining sensitivity as high as 3100 nm/RIU.

  20. Birefringence effects in multi-core fiber: coupled local-mode theory.

    Science.gov (United States)

    Macho, Andrés; García-Meca, Carlos; Fraile-Peláez, F Javier; Morant, Maria; Llorente, Roberto

    2016-09-19

    In this paper, we evaluate experimentally and model theoretically the intra- and inter-core crosstalk between the polarized core modes in single-mode multi-core fiber media including temporal and longitudinal birefringent effects. Specifically, extensive experimental results on a four-core fiber indicate that the temporal fluctuation of fiber birefringence modifies the intra- and inter-core crosstalk behavior in both linear and nonlinear optical power regimes. To gain theoretical insight into the experimental results, we introduce an accurate multi-core fiber model based on local modes and perturbation theory, which is derived from the Maxwell equations including both longitudinal and temporal birefringent effects. Numerical calculations based on the developed theory are found to be in good agreement with the experimental data. PMID:27661883

  1. Highly birefringent extruded elliptical-hole photonic crystal fibers with single defect and double defects

    Institute of Scientific and Technical Information of China (English)

    Zhongjiao He

    2009-01-01

    Highly birefringent elliptical-hole photonic crystal fibers(PCFs)with single defect and double defects are proposed,which are suppoosed to be achieved by extruding normal circular-hole PCFs based on a triangular lattice photonic crystal structure.Comparative research on the birefringence and the confinement loss of the proposed PCFs with single defect and double defects is presented.Simulation results show that the proposed PCFs with single defect and double defects can be with high birefringence(even up to the order of 10-2).The confinement loss increases when the ellipticity of the air hole of the PCFs increases,which nevertheless can be overconle by increasing the ring number or the area of the air holes in the fiber cladding.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  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. EPOXY-BASED AZO POLYMERS WITH HIGH CHROMOPHORE DENSITY:SYNTHESIS, CHARACTERIZATION AND PHOTOINDUCED BIREFRINGENCE

    Institute of Scientific and Technical Information of China (English)

    Xiao-lin Wang; Xiao-gong Wang

    2012-01-01

    Three epoxy-based azo polymers (PEP-AZ-C1,PEP-AZ-CN and PEP-AZ-NT) with high chromophore density were synthesized by using post-polymerization azo-coupling reactions between epoxy-bascd precursor polymer (PEP-AN)and diazonium salts of 4-chloroaniline,4-aminobenzonitrile and 4-nitroaniline,respectively.The structures and properties of the azo polymers were characterized by using 1H-NMR,FT-IR,UV-Vis and thermal analyses.The photoinduced birefringence of the azo polymers was studied by irradiating spin-coated films of the polymers with laser beam at three different wavelengths (488,532,and 589 nm).The results indicate that the photoinduced birefringence of the azo polymers is related with the electron-withdrawing group on azo chromophores and the excitation wavelength.The excitation wavelength that can cause the efficient responses is determined by the absorption band positions of the azo chromophores,which are mainly affected by the electron-withdrawing group on the chromophores.Therefore,the azo polymers containing chromophores with different electron-withdrawing groups show different responsive behavior to the irradiation light at different wavelengths.When irradiated with 488 nm light,PEP-AZ-Cl shows the shortest time to reach the saturated birefringence but with the lowest saturation birefringence level compared with the other two azo polymers.When irradiated with 532 nm light,PEP-AZ-CN shows the shortest time to reach the saturated birefringence.When irradiated with 532 and 589 nm light,PEP-AZ-NT shows the highest saturation birefringence level.

  10. Influence of Optical Feedback from Birefringence External Cavity on Intensity Tuning and Polarization of Laser

    Institute of Scientific and Technical Information of China (English)

    FEI Li-Gang; ZHANG Shu-Lian; WAN Xin-Jun

    2004-01-01

    The characteristics of intensity tuning and polarization of He-Ne laser with optical feedback are studied. When the internal cavity length of the laser with birefringence optical feedback is tuned, not only does output intensity vary with laser frequency, but also the polarization periodically hops between two orthogonal directions. Ff the phase difference of birefringence is π/2, two polarization states alternately oscillate and have equal bandwidths within the longitudinal mode spacing. The times of polarization flipping in the longitudinal mode bandwidth is proportional to the ratio of external cavity length to internal cavity length. The experimental results are explained, and the potential uses are also discussed.

  11. 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

  12. 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

  13. Highly birefringent suspended-core photonic microcells for refractive-index sensing

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chao [Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong (China); The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057 (China); Jin, Wa; Ma, Jun; Jin, Wei, E-mail: eewjin@polyu.edu.hk; Yang, Fan; Ho, Hoi Lut [Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong (China); Liao, Changrui; Wang, Yiping [Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education/Guangdong Province, Shenzhen University, Shenzhen 518060 (China)

    2014-08-11

    An in-line photonic microcell with a highly birefringent suspended microfiber core is fabricated by locally heating and pressurizing selected air-holes of an endless single mode photonic crystal fiber. The microfiber core has rhombus-like cross-sectional geometry and could achieve a high birefringence of up to 10{sup −2}. The microfiber core is fixed at the center of the microcell by thin struts attached to an outer jacket tube, which protects and isolates the microfiber from environmental contaminations. Highly sensitive and robust refractive index sensors based on such microcells are experimentally demonstrated.

  14. 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.

  15. 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

    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...

  16. Effect of Third-order Dispersion of Birefringent Fiber on Pulse Transmission

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of thirdorder dispersion on pulse transmission is discussed. The coupled nonlinear Schrdinger equations characterizing the birefringent singlemode fibers is solved numerically with combined consideration on chromatic dispersion, including second and thirdorder dispersions, polarization mode dispersion (PMD) and nonlinearity. Various simulation results are presented.

  17. 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.

  18. 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.

  19. Design of low-confinement-loss and highly birefringent index-guiding photonic crystal fibers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fang-di; XU Zheng-kai; YE Pei-da

    2008-01-01

    We present a systematic scheme to achieve both high birefringence and low confinement loss in index-guiding photonic crystal fibers (PCFs),using a structurally-simple PCF with finite number of air holes in the cladding region.By increasing the size of the outermost-ring air holes in the cladding region,highly birefringent PCFs with low confinement loss can be successfully achieved.The design strategy is based on the fact that the modal birefringence of PCFs is dominated by the inner-ring air holes in PCF,which is verified by a full-vector finite element method with anisotropic perfectly matched layers.Numerical results show that modal birefringence in the order of 10.3 and confinement loss less than 0.1 dB/km can be easily realized in the proposed PCF with only four rings of air holes in the cladding region.We expect that such fibers will be much easier to be fabvicated than those with more air holes in the cladding region.

  20. 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.

  1. 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.

  2. Birefringent vertical cavity surface-emitting lasers: toward high-speed spin-lasers

    Science.gov (United States)

    Gerhardt, Nils C.; Lindemann, Markus; Pusch, Tobias; Michalzik, Rainer; Hofmann, Martin R.

    2016-04-01

    Spin-polarized vertical-cavity surface-emitting lasers (spin-VCSELs) provide novel opportunities to overcome several limitations of conventional, purely charge-based semiconductor lasers. Presumably the highest potential lies in the spin-VCSEL's capability for ultrafast spin and polarization dynamics which can be significantly faster than the intensity dynamics in conventional devices. By injecting spin-polarized carriers, these coupled spin-photon dynamics can be controlled and utilized for high-speed applications. While relaxation oscillations provide insights in the speed and direct modulation bandwidth of conventional devices, resonance oscillations in the circular polarization degree step in for the spin and polarization dynamics in spin-VCSELs. These polarization oscillations can be generated using pulsed spin injection and achieve much higher frequencies than the conventional intensity relaxation oscillations in these devices. Furthermore polarization oscillations can be switched on and off and it is possible to generate short polarization pulses, which may represent an information unit in polarization-based optical communication. The frequency of polarization oscillations is mainly determined by the birefringence-induced mode splitting between both orthogonal linearly polarized laser modes. Thus the polarization modulation bandwidth of spin-VCSELs can be increased by adding a high amount of birefringence to the cavity, for example by incorporating mechanical strain. Using this technique, we could demonstrate tunable polarization oscillations from 10 to 40 GHz in AlGaAs-based 850nm VCSELs recently. Furthermore a birefringence-induced mode splitting of more than 250 GHz could be demonstrated experimentally. Provided that this potential for ultrafast dynamics can be fully exploited, birefringent spin-VCSELs are ideal devices for fast short-haul optical interconnects. In this paper we review our recent progress on polarization dynamics of birefringent spin

  3. 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.

  4. 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...

  5. Spectral-domain measurement of the strain sensitivity of phase modal birefringence of polarization-maintaining optical fibers

    Science.gov (United States)

    Kaczmarek, Cezary

    2016-09-01

    The paper presents a new and simple method of measuring the strain sensitivity of phase modal birefringence (dΔn/dε) of polarization maintaining fibers (PMFs). The method is based on measuring the spectral strain sensitivity of a strain sensor in the configuration of a Sagnac interferometer with a PMF. The measured spectral strain sensitivity of the sensor is used to determine the strain sensitivity of phase modal birefringence and the polarimetric strain sensitivity of the PMF. In addition, a new procedure for determining the sign of the strain sensitivity of phase and group modal birefringence of a PMF. Using this method, measurements of the strain sensitivity of modal birefringence of PMFs were performed: a PM-PCF and a Bow-Tie fiber, in the wavelength range 1460-1600 nm. A comparison of the results of these measurements with results obtained using other methods for the same types of fibers is presented.

  6. Segment Orientation and Optical Birefringence of Amorphous Polymers Under Tensile Deformation: Novel Computational Method applied to Different Glassy Polycarbonates

    Science.gov (United States)

    Natarajan, Upendra; Sulatha, M. S.

    2005-03-01

    Orientation dependent optical properties of Bisphenol A polycarbonate and two aliphatic substituted polycarbonates in glassy phase have been studied by atomistic modeling using molecular mechanics simulations under tensile deformation. Probability distributions and orientation functions show that phenylene rings and carbonate groups vectors along the main chain orient towards stretching direction following deformation. Interchain packing of rings and carbonates become ordered with strain. Efficient computational approach for calculation of optical birefringence of amorphous polymers is presented and applied to the polycarbonates in detail. Polarizability anisotropy of the polymer segments and chain as a function of deformation is calculated by combining information on the conformations and group polarizabilities, and used to estimate birefringence during deformation. Simulated and experimental values for segment orientation and bulk birefringence are in very good agreement. Effect of the optical properties of atomic groups on bulk birefringence is brought forth for the first time by molecular simulation for polymers other than polyethylene.

  7. 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.

  8. 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.

  9. 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.

  10. A novel synthesis approach for birefringent filters having arbitrarily amplitude transmittances

    Science.gov (United States)

    Halassi, Abde Rezzaq; Hamdi, Rachid; Bendimerad, Djalal Falih; Benkelfat, Badr-Eddine

    2016-06-01

    In this paper, we present a novel procedure for the synthesis of a filter having an arbitrarily specified amplitude transmittance. The filter configuration consists of N birefringent stages placed between a polarizer and an analyzer, with each stage containing an identical section and a variable section. An additional variable section is placed in front of the analyzer. The synthesis procedure is based on the resolution of a generalized nonlinear equation system directly deducted from the Jones matrix formalism to determine the angles of each stage, the angle of the analyzer and the phase shifts of the variable sections. A typical example of a 6-stage birefringent filter having an arbitrarily non-symmetric amplitude transmittance is shown and the opto-geometrical parameters are given to demonstrate the efficiency of the proposed synthesis procedure. The results obtained show an excellent agreement with those developed in the literature.

  11. 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.

  12. 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

  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. Longitudinal coherence properties of light waves propagating through a birefringent fiber.

    Science.gov (United States)

    Tsubokawa, M; Shibata, N; Higashi, T; Seikai, S

    1987-05-01

    Longitudinal coherence properties of the waves propagating through a birefringent fiber are investigated theoretically and experimentally. Significant loss due to the polarization-dispersion slope is observed clearly for the interference between the two orthogonally polarized HE(11) modes. The results obtained experimentally reflect the theoretical predictions well for both the modulus of the degree of coherence and its curve shape versus the optical path difference in the wavelength region from 816 to 1540 nm.

  15. 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.

  16. Distributed Measurement of Birefringence by P-OTDR Assisted with Piezoelectric Polarization Controller

    Institute of Scientific and Technical Information of China (English)

    YANG Shuang-Shou; WU Chong-Qing; LI Zheng-Yong; ZHANG Ren-Yuan; MENG Qing-Wen

    2008-01-01

    We propose a new polarization sensitive optical time domain reflectometry (P-OTDR) setup assisted with a piezoelectric polarization controller (PPC). The input state of polarization can be changed by varying the voltage of PPC without any rotatable instrument, and only one optical receiver is used to detect the backward beam.We measure a single mode fibre and get the distribution of birefringence along the SMF.

  17. 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)

  18. 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 ...

  19. 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.

  20. 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 ...

  1. 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.

  2. 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.

  3. 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.

  4. 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 ...

  5. 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.

  6. 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.

  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. An Optimal Cure Process to Minimize Residual Void and Optical Birefringence for a LED Silicone Encapsulant

    Directory of Open Access Journals (Sweden)

    Min-Jae Song

    2014-05-01

    Full Text Available Silicone resin has recently attracted great attention as a high-power Light Emitting Diode (LED encapsulant material due to its good thermal stability and optical properties. In general, the abrupt curing reaction of the silicone resin for the LED encapsulant during the curing process induces reduction in the mechanical and optical properties of the LED product due to the generation of residual void and moisture, birefringence, and residual stress in the final formation. In order to prevent such an abrupt curing reaction, the reduction of residual void and birefringence of the silicone resin was observed through experimentation by introducing the multi-step cure processes, while the residual stress was calculated by conducting finite element analysis that coupled the heat of cure reaction and cure shrinkage. The results of experiment and analysis showed that it was during the three-step curing process that the residual void, birefringence, and residual stress reduced the most in similar tendency. Through such experimentation and finite element analysis, the study was able to confirm that the optimization of the LED encapsulant packaging process was possible.

  10. Novel laser machining of optical fibers for long cavities with low birefringence.

    Science.gov (United States)

    Takahashi, Hiroki; Morphew, Jack; Oručević, Fedja; Noguchi, Atsushi; Kassa, Ezra; Keller, Matthias

    2014-12-15

    We present a novel method of machining optical fiber surfaces with a CO₂ laser for use in Fiber-based Fabry-Perot Cavities (FFPCs). Previously FFPCs were prone to large birefringence and limited to relatively short cavity lengths (≤ 200 μm). These characteristics hinder their use in some applications such as cavity quantum electrodynamics with trapped ions. We optimized the laser machining process to produce large, uniform surface structures. This enables the cavities to achieve high finesse even for long cavity lengths. By rotating the fibers around their axis during the laser machining process the asymmetry resulting from the laser's transverse mode profile is eliminated. Consequently we are able to fabricate fiber mirrors with a high degree of rotational symmetry, leading to remarkably low birefringence. Through measurements of the cavity finesse over a range of cavity lengths and the polarization dependence of the cavity linewidth, we confirmed the quality of the produced fiber mirrors for use in low-birefringence FFPCs.

  11. Microwave birefringent metamaterials for polarization conversion based on spoof surface plasmon polariton modes

    Science.gov (United States)

    Li, Yongfeng; Zhang, Jieqiu; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Feng, Dayi; Xu, Zhuo; Qu, Shaobo

    2016-01-01

    We propose the design of wideband birefringent metamaterials based on spoof surface plasmon polaritons (SSPPs). Spatial k-dispersion design of SSPP modes in metamaterials is adopted to achieve high-efficiency transmission of electromagnetic waves through the metamaterial layer. By anisotropic design, the transmission phase accumulation in metamaterials can be independently modulated for x- and y-polarized components of incident waves. Since the dispersion curve of SSPPs is nonlinear, frequency-dependent phase differences can be obtained between the two orthogonal components of transmitted waves. As an example, we demonstrate a microwave birefringent metamaterials composed of fishbone structures. The full-polarization-state conversions on the zero-longitude line of Poincaré sphere can be fulfilled twice in 6–20 GHz for both linearly polarized (LP) and circularly polarized (CP) waves incidence. Besides, at a given frequency, the full-polarization-state conversion can be achieved by changing the polarization angle of the incident LP waves. Both the simulation and experiment results verify the high-efficiency polarization conversion functions of the birefringent metamaterial, including circular-to-circular, circular-to-linear(linear-to-circular), linear-to-linear polarization conversions. PMID:27698443

  12. Characteristics of Highly Birefringent Photonic Crystal Fiber with Defected Core and Equilateral Pentagon Architecture

    Directory of Open Access Journals (Sweden)

    Fei Yu

    2016-01-01

    Full Text Available A novel high birefringence and nearly zero dispersion-flattened photonic crystal fiber (PCF with elliptical defected core (E-DC and equilateral pentagonal architecture is designed. By applying the full-vector finite element method (FEM, the characteristics of electric field distribution, birefringence, and chromatic dispersion of the proposed E-DC PCF are numerically investigated in detail. The simulation results reveal that the proposed PCF can realize high birefringence, ranging from 10-3 to 10-2 orders of magnitude, owing to the embedded elliptical air hole in the core center. However, the existence of the elliptical air hole gives rise to an extraordinary electric field distribution, where a V-shaped notch appears and the size of the V-shaped notch varies at different operating wavelengths. Also, the mode field diameter is estimated to be about 2 μm, which implies the small effective mode area and highly nonlinear coefficient. Furthermore, the investigation of the chromatic dispersion characteristic shows that the introduction of the elliptical air hole is helpful to control the chromatic dispersion to be negative or nearly zero flattened over a wide wavelength bandwidth.

  13. 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.

  14. Microwave birefringent metamaterials for polarization conversion based on spoof surface plasmon polariton modes

    Science.gov (United States)

    Li, Yongfeng; Zhang, Jieqiu; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Feng, Dayi; Xu, Zhuo; Qu, Shaobo

    2016-10-01

    We propose the design of wideband birefringent metamaterials based on spoof surface plasmon polaritons (SSPPs). Spatial k-dispersion design of SSPP modes in metamaterials is adopted to achieve high-efficiency transmission of electromagnetic waves through the metamaterial layer. By anisotropic design, the transmission phase accumulation in metamaterials can be independently modulated for x- and y-polarized components of incident waves. Since the dispersion curve of SSPPs is nonlinear, frequency-dependent phase differences can be obtained between the two orthogonal components of transmitted waves. As an example, we demonstrate a microwave birefringent metamaterials composed of fishbone structures. The full-polarization-state conversions on the zero-longitude line of Poincaré sphere can be fulfilled twice in 6–20 GHz for both linearly polarized (LP) and circularly polarized (CP) waves incidence. Besides, at a given frequency, the full-polarization-state conversion can be achieved by changing the polarization angle of the incident LP waves. Both the simulation and experiment results verify the high-efficiency polarization conversion functions of the birefringent metamaterial, including circular-to-circular, circular-to-linear(linear-to-circular), linear-to-linear polarization conversions.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Optical characterization of the nematic lyotropic chromonic liquid crystals: light absorption, birefringence, and scalar order parameter.

    Science.gov (United States)

    Nastishin, Yu A; Liu, H; Schneider, T; Nazarenko, V; Vasyuta, R; Shiyanovskii, S V; Lavrentovich, O D

    2005-10-01

    We report on the optical properties of the nematic (N) phase formed by lyotropic chromonic liquid crystals (LCLCs) in well aligned planar samples. LCLCs belong to a broad class of materials formed by one-dimensional molecular self-assembly and are similar to other systems such as "living polymers" and "wormlike micelles." We study three water soluble LCLC forming materials: disodium chromoglycate, a derivative of indanthrone called Blue 27, and a derivative of perylene called Violet 20. The individual molecules have a planklike shape and assemble into rodlike aggregates that form the phase once the concentration exceeds about 0.1 M. The uniform surface alignment of the N phase is achieved by buffed polyimide layers. According to the light absorption anisotropy data, the molecular planes are on average perpendicular to the aggregate axes and thus to the nematic director. We determined the birefringence of these materials in the N and biphasic N-isotropic (I) regions and found it to be negative and significantly lower in the absolute value as compared to the birefringence of typical thermotropic low-molecular-weight nematic materials. In the absorbing materials Blue 27 and Violet 20, the wavelength dependence of birefringence is nonmonotonic because of the effect of anomalous dispersion near the absorption bands. We describe positive and negative tactoids formed as the nuclei of the new phase in the biphasic N-I region (which is wide in all three materials studied). Finally, we determined the scalar order parameter of the phase of Blue 27 and found it to be relatively high, in the range 0.72-0.79, which puts the finding into the domain of general validity of the Onsager model. However, the observed temperature dependence of the scalar order parameter points to the importance of factors not accounted for in the athermal Onsager model, such as interaggregate interactions and the temperature dependence of the aggregate length.

  20. 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.

  1. 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

  2. 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)

  3. Gravity-induced birefringence within the framework of Poincare gauge theory

    CERN Document Server

    Preuss, O; Haugan, Mark P; Jordan, S; Preuss, Oliver; Solanki, Sami K.; Jordan, Stefan

    2005-01-01

    Gauge theories of gravity provide an elegant and promising extension of general relativity. In this paper we show that the Poincar\\'e gauge theory exhibits gravity-induced birefringence under the assumption of a specific gauge invariant nonminimal coupling between torsion and Maxwell's field. Furthermore we give for the first time an explicit expression for the induced phaseshift between two orthogonal polarization modes within the Poincar\\'e framework. Since such a phaseshift can lead to a depolarization of light emitted from an extended source this effect is, in principle, observable. We use white dwarf polarimetric data to constrain the essential coupling constant responsible for this effect.

  4. Repeating pulsed magnet system for axion-like particle searches and vacuum birefringence experiments

    Science.gov (United States)

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

    2016-10-01

    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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Thermal Stress-Induced Birefringence in Borate Glass Irradiated by Femtosecond Laser Pulses

    Institute of Scientific and Technical Information of China (English)

    DAI Ye; YU Bing-Kun; LU Bo; QIU Jian-Rong; YAN Xiao-Na; JIANG Xiong-Wei; ZHU Cong-Shan

    2005-01-01

    @@ Thermal stress-induced birefringence in borate glass which has been irradiated by 800-nm femtosecond laser pulses is observed under cross-polarized light. Due to the high temperature and pressure formed in the focal volume, the material at the edge of the micro-modified region is compressed between the expanding region and the unheated one, then stress emerges. Raman spectroscopy is used to investigate the stress distribution in the micro-modified region and indicates the redistributions of density and refractive index by Raman peak shift. We suggest that this technique can develop waveguide polarizers and Fresnel zone plates in integrated optics.

  10. 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.

  11. 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.

  12. Vector modulational instability induced by parametric resonance in periodically tapered highly-birefringent optical fibers

    CERN Document Server

    Armaroli, Andrea

    2013-01-01

    We study the modulational instability induced by periodic variations of group-velocity dispersion and nonlinear coefficients in a highly birefringent fiber. We observe, for each resonance order, the presence of two pairs of genuine vector type sidebands, which are spectrally unbalanced between the polarization components for nonzero group-index mismatch, and one pair of balanced sidebands emerging and dominating at increasing group-index mismatch. As the conventional modulational instability manifests itself, it is partially suppressed by the proximity of these new unstable regions.

  13. Correlation between randomly varying birefringence and random dispersion map in a dispersion-managed soliton system

    Institute of Scientific and Technical Information of China (English)

    Li Hong; Wang Tie-Jun; Huang De-Xiu

    2004-01-01

    The correlation between perturbations caused by randomly varying birefringence and a random dispersion map is considered in a dispersion-managed soliton system, and their effects on soliton propagation and interaction are investigated numerically. These perturbations lead to the disintegration of a soliton, and enhance the interaction between solitons. The correlation plays an important role, and reinforces these effects. Furthermore, there is a stochastic resonance between two perturbations in the system; here the effect is the largest, and the corresponding distance until disintegration is the shortest. Finally, nonlinear gain and a filter are introduced to effectively suppress these effects.

  14. 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.

  15. Refractive indices and birefringence of hybrid liquid crystal - nanoparticles composite materials in the terahertz region

    Directory of Open Access Journals (Sweden)

    E. Mavrona

    2015-07-01

    Full Text Available We show that a hybrid LC-ferroelectric nanoparticle suspension of liquid crystal E7 doped with BaTiO3 nanoparticles leads to 10% increase in birefringence in the THz region of spectrum as compared to pure E7. Doped liquid crystals can be used to increase performance of THz modulators and waveplates. BaTiO3 nanoparticles used in the mixture were synthesised with the sol gel technique, and their refractive index has been measured in THz in powder form and in solution.

  16. 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.

  17. 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....

  18. 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....

  19. Large Microwave Birefringence Liquid-Crystal Characterization for Phase-Shifter Applications

    Science.gov (United States)

    Dubois, Frédéric; Krasinski, Freddy; Splingart, Bertrand; Tentillier, Nicolas; Legrand, Christian; Spadlo, Anna; Dabrowski, Roman

    2008-05-01

    This work is concerned with the improvement of a microwave liquid-crystal phase shifter using a large birefringence nematic liquid crystal. This material is a eutectic mixture of isothiocyanatotolane molecules. Microwave dielectric properties are reported and compared to the data obtained with the 5CB cyanobiphenyl material in the 26-40 GHz frequency range using a rectangular waveguide. The phase-shifter design consists of a central cavity, where a liquid crystal is inserted, and two coplanar strip lines accesses. Its dimensions were calculated by electromagnetic simulation, using measured dielectric permittivities of the liquid crystal. The measurements were performed with a commercial Wiltron 3680 K probe test fixture. Phase-shift variations with and without bias voltage versus frequency are presented. As expected, the large-birefringence nematic liquid crystal exhibits a higher microwave dielectric anisotropy (Δɛ' = 1.06 against 0.34) and the tunability of the phase shifter strongly increases (1.8 deg·cm-1·GHz-1 against 0.8 deg·cm-1·GHz-1).

  20. Effect of mechanical stress on optical properties of polydimethylsiloxane II - Birefringence

    Science.gov (United States)

    Tarjányi, Norbert; Turek, Ivan; Martinček, Ivan

    2014-11-01

    In the paper we present the results of an experimental study of photoelasticity of polydimethylsiloxane (PDMS) in its deformation in compression with relative shortening in the range in which the dependence of the mechanical stress is not a linear function of strain (up to ε = -0.45). We observed nonlinearity of the dependence of the refractive index difference between beams polarized parallel and perpendicular to the direction in which the sample is compressed on the deformation which is significantly lower than the nonlinearity of the stress-strain dependence measured at the same sample. This fact can be explained by the assumption that the birefringence involves two mechanisms: (i) a change in polarizability of atoms, which is proportional to stress and, (ii) a change in structure of the environment, which we assume to be a linear function of strain. Appropriate choice of the impact ratio of these mechanisms gives a good match between experimentally observed dependence of birefringence on deformation and dependence arising from the above mentioned assumption. The contribution of the individual effects to the observed photoelasticity we investigated within the wavelength range (400-1800) nm. We have found that: (i) the effect of the polarizability of the environment is dominant for strain larger than ε = -0.3; (ii) the difference in the refractive indices of the beams with different orientation of polarization slightly decreases with increasing wavelength and, (iii) there are visible less-pronounced local extremes in the vicinity of the absorption lines of PDMS in the near-infrared.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Measurements of linear and circular birefringence in metals by femtosecond optical pump-probe spectroscopy

    CERN Document Server

    Wilks, R

    2002-01-01

    Optically induced transient linear and circular birefringence has been studied in three different materials: ferromagnetic Ni, semiconducting GaAs and the non-magnetic metal Al. A pump-probe experiment with sub-ps resolution was set up for this purpose. The time-resolved reflectivity, rotation and ellipticity of the reflected probe beam were recorded after pumping with light of variable helicity. In the Ni sample an ultrafast demagnetisation effect was observed and the variation of the rotation and ellipticity on sub-picosecond time scales was compared. Rotation and ellipticity were found to have a similar time dependence. In GaAs, optical orientation of spin was achieved and the subsequent spin relaxation was measured for different pump powers. Fitting of the optical rotation data has revealed the power dependence of the various decay constants. In the Al sample a small signal was observed that decays on ps time scales. This was attributed to a linear birefringence effect resulting from a cubic optical nonli...

  10. 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.

  11. 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

  12. 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...

  13. 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.

  14. A New Distributed Measurement of Birefringence Vectors by P-OTDR Assisted by a High Speed Polarization Analyzer

    Institute of Scientific and Technical Information of China (English)

    SHANG Chao; WU Chong-Qing; LI Zheng-Yong; YANG Shuang-Show

    2011-01-01

    A new polarimetric optical time domain reflectometry (P-OTDR) measurement device assisted by a high speed polarization analyzer is designed and a new algorithm, which can be used to accurately measure the birefringence vector, is proposed. In this method, only one measurement is required and the result is insensitive to the input state of polarization. An 1-km single mode fiber (SMF) is measured and the distribution of the local birefringence vector along the SMF is obtained with a resolution of 2 cm.%@@ A new polarimetric optical time domain reflectometry(P-OTDR)measurement device assisted by a high speed polarization analyzer is designed and a new algorithm,which can be used to accurately measure the birefringence vector,is proposed.In this method,only one measurement is required and the result is insensitive to the input state of polarization.An 1-km single mode fiber(SMF)is measured and the distribution of the local birefringence vector along the SMF is obtained with a resolution of 2 cm.

  15. 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.

  16. 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.

  17. 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.

  18. 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 ...

  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. High-resolution birefringence cartography of a vertical cavity semiconductor laser

    CERN Document Server

    Wang, T

    2015-01-01

    We report on spatially resolved birefringence measurements in a multimode vertical-cavity surface-emitting laser (VCSEL) by using the emission wavelength distribution mapping. The point-by-point, polarization-resolved spectral information lends itself to the identification of anisotropies in the material and enables the estimate of refractive index differences and gradients in the two orthogonal polarization components with high spatial resolution. Compared with classical optical microscopy techniques, we can easily recognize the position of the emission wavelength split (which carefully points to the position of defects) with a much better spectral sensitivity (potentially as low as 3 GHz). The presented method is general and can be used with any bulk, light-emitting source (even passive, if external illumination is added) and may prove very useful for device fabrication, quality checks and process improvements.

  1. 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...

  2. 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

  3. 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.

  4. High resolution polarization-independent high-birefringence fiber loop mirror sensor.

    Science.gov (United States)

    Leandro, Daniel; Bravo, Mikel; Lopez-Amo, Manuel

    2015-11-30

    In this work, two all polarization-maintaining (PM) high-birefringence (Hi-Bi) fiber loop mirrors (FLM) which are immune to external polarization perturbations are validated both theoretically and experimentally. Simplified and stable versions of classical FLMs were attained using a PM-coupler and by fusing the different Hi-Bi fiber sections with an adequate rotation angle between them. Since the polarization states are fixed along the whole fiber loop, no polarization controllers are needed. This simplifies the operation and increases the stability of the systems, which were also validated as ultra-high resolution sensors, experimentally obtaining a resolution of 6.2∙10-4 °C without averaging. PMID:26698729

  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. 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.

  7. 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

  8. 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.

  9. Transient birefringence of liquids induced by terahertz electric-field torque on permanent molecular dipoles

    CERN Document Server

    Sajadi, Mohsen; Kampfrath, Tobias

    2016-01-01

    Microscopic understanding of low-frequency molecular motions in liquids has been a longstanding goal in soft-matter science. So far, such low-frequency motions have mostly been accessed indirectly by off-resonant optical pulses. A more direct approach would be to interrogate the dynamic structure of liquids with terahertz (THz) radiation. Here, we provide evidence that resonant excitation with intense THz pulses is capable of driving reorientational-librational modes of aprotic polar liquids through coupling to the permanent molecular dipole moments. We observe a hallmark of this enhanced coupling: a transient optical birefringence up to an order of magnitude higher than obtained with optical excitation. Our results open up the path to applications such as efficient molecular alignment and systematic study of the coupling of rotational motion to other collective motions in liquids.

  10. 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.

  11. Neural network calibration of a snapshot birefringent Fourier transform spectrometer with periodic phase errors.

    Science.gov (United States)

    Luo, David; Kudenov, Michael W

    2016-05-16

    Systematic phase errors in Fourier transform spectroscopy can severely degrade the calculated spectra. Compensation of these errors is typically accomplished using post-processing techniques, such as Fourier deconvolution, linear unmixing, or iterative solvers. This results in increased computational complexity when reconstructing and calibrating many parallel interference patterns. In this paper, we describe a new method of calibrating a Fourier transform spectrometer based on the use of artificial neural networks (ANNs). In this way, it is demonstrated that a simpler and more straightforward reconstruction process can be achieved at the cost of additional calibration equipment. To this end, we provide a theoretical model for general systematic phase errors in a polarization birefringent interferometer. This is followed by a discussion of our experimental setup and a demonstration of our technique, as applied to data with and without phase error. The technique's utility is then supported by comparison to alternative reconstruction techniques using fast Fourier transforms (FFTs) and linear unmixing.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. In vivo birefringence and thickness measurements of the human retinal nerve fiber layer using polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Cense, Barry; Chen, Teresa C; Park, B Hyle; Pierce, Mark C; de Boer, Johannes F

    2004-01-01

    Glaucoma causes damage of the nerve fiber layer, which may cause loss of retinal birefringence. Therefore, PS-OCT is a potentially useful technique for the early detection of glaucoma. We built a fiber-based PS-OCT setup that produces real-time images of the human retina in vivo, coregistered with retinal video images of the location of PS-OCT scans. Preliminary measurements of a healthy volunteer show that the double-pass phase retardation per unit of depth of the RNFL is not constant and varies with location, with values between 0.18 and 0.37 deg/microm. A trend in the preliminary measurements shows that the nerve fiber layer located inferior and superior to the optic nerve head is more birefringent than the thinner layer of nerve fiber tissue in the temporal and nasal regions. PMID:14715063

  18. Invivo depth-resolved birefringence measurements of the human retinal nerve fiber layer by polarization-sensitive optical coherence tomography.

    Science.gov (United States)

    Cense, Barry; Chen, Teresa C; Park, B Hyle; Pierce, Mark C; de Boer, Johannes F

    2002-09-15

    To our knowledge, this is the first demonstration of in vivo depth-resolved birefringence measurements of the human retinal nerve fiber layer (RNFL) by use of polarization-sensitive optical coherence tomography (PS-OCT). Because glaucoma causes nerve fiber layer damage, which may cause loss of retinal birefringence, PS-OCT is a potentially useful technique for the early detection of glaucoma. We built a fiber-based PS-OCT setup that produces quasi-real-time images of the human retina in vivo . Preliminary measurements of a healthy volunteer showed that the double-pass phase retardation per unit depth of the RNFL near the optic nerve head is 39+/-6( degrees )/100microm . PMID:18026517

  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. 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.

  1. 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

  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. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Sutter, John P., E-mail: john.sutter@diamond.ac.uk; Dolbnya, Igor P.; Collins, Stephen P. [Diamond Light Source Ltd., Chilton, Didcot, Oxfordshire OX11 0DE (United Kingdom); Harris, Kenneth D. M.; Edwards-Gau, Gregory R. [School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales (United Kingdom); Palmer, Benjamin A. [Department of Structural Biology, Weizmann Institute of Science, 234 Herzl St., Rehovot 7610001 (Israel)

    2015-04-28

    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.

  5. 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.

  6. Open source software for electric field Monte Carlo simulation of coherent backscattering in biological media containing birefringence.

    Science.gov (United States)

    Radosevich, Andrew J; Rogers, Jeremy D; Capoğlu, Ilker R; Mutyal, Nikhil N; Pradhan, Prabhakar; Backman, Vadim

    2012-11-01

    ABSTRACT. We present an open source electric field tracking Monte Carlo program to model backscattering in biological media containing birefringence, with computation of the coherent backscattering phenomenon as an example. These simulations enable the modeling of tissue scattering as a statistically homogeneous continuous random media under the Whittle-Matérn model, which includes the Henyey-Greenstein phase function as a special case, or as a composition of discrete spherical scatterers under Mie theory. The calculation of the amplitude scattering matrix for the above two cases as well as the implementation of birefringence using the Jones N-matrix formalism is presented. For ease of operator use and data processing, our simulation incorporates a graphical user interface written in MATLAB to interact with the underlying C code. Additionally, an increase in computational speed is achieved through implementation of message passing interface and the semi-analytical approach. Finally, we provide demonstrations of the results of our simulation for purely scattering media and scattering media containing linear birefringence.

  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. 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.

  9. 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)

  10. 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 ...

  11. 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.

  12. 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...

  13. A birefringent polarization modulator: Application to phase measurement in conoscopic interference patterns.

    Science.gov (United States)

    Veiras, F E; Garea, M T; Perez, L I

    2016-04-01

    Conoscopic interferometry for crystal characterization is a very well-known technique with increasing applications in different fields of technology. The advantage of the scheme proposed here is the introduction of a polarization modulator that allows the recovery of the phase information contained in conoscopic interferograms. This represents a real advantage since the most relevant physical information of the sample under study is usually contained in the phase of the fringe pattern. Moreover, this technique works successfully even when there are no visible fringes. The setup employed is a simple conoscopic interferometer where the elements under study correspond to two birefringent crystal slabs and a commercial mica wave plate. It allows the crystals to be characterized and the wave plate retardance to be measured as a function of the angle of incidence. The modulator itself consists of a single tiltable crystal plate which, by means of phase shifting techniques, permits the recovery of a phase map for each sample. It is inexpensive and it can be easily calibrated, so it works with a wide range of phase shifting interferometry algorithms. We show that our scheme is easily adaptable to algorithms that require either a low or high amount of interferograms.

  14. A hybrid tunable THz metadevice using a high birefringence liquid crystal

    Science.gov (United States)

    Chikhi, Nassim; Lisitskiy, Mikhail; Papari, Gianpaolo; Tkachenko, Volodymyr; Andreone, Antonello

    2016-01-01

    We investigate a hybrid re-configurable three dimensional metamaterial based on liquid crystal as tuning element in order to build novel devices operating in the terahertz range. The proposed metadevice is an array of meta-atoms consisting of split ring resonators having suspended conducting cantilevers in the gap region. Adding a “third dimension” to a standard planar device plays a dual role: (i) enhance the tunability of the overall structure, exploiting the birefringence of the liquid crystal at its best, and (ii) improve the field confinement and therefore the ability of the metadevice to efficiently steer the THz signal. We describe the design, electromagnetic simulation, fabrication and experimental characterization of this new class of tunable metamaterials under an externally applied small voltage. By infiltrating tiny quantities of a nematic liquid crystal in the structure, we induce a frequency shift in the resonant response of the order of 7–8% in terms of bandwidth and about two orders of magnitude change in the signal absorption. We discuss how such a hybrid structure can be exploited for the development of a THz spatial light modulator. PMID:27708395

  15. 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

  16. 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...

  17. 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

  18. 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.

  19. Dark soliton interaction in optical time division multiplexed system with randomly varying birefringence and random dispersion map

    Institute of Scientific and Technical Information of China (English)

    Hong Li(李宏); Tiejun Wang(王铁军); Dexiu Huang(黄德修)

    2004-01-01

    Correlated perturbations caused by both randomly varying birefringence and random dispersion map are considered in optical time division multiplexed dispersion-managed dark soliton system, and their effects on soliton interaction are investigated numerically. These perturbations enhance soliton interaction, and their effects relate to the strength of perturbation, separation, and pulse width. The correlation plays an important role and reinforces these effects. Moreover, there is a stochastic limit between two perturbations in the system, where the effect is the largest and the corresponding interaction distance is the shortest.

  20. Photonic-chip-based all-optical ultra-wideband pulse generation via XPM and birefringence in a chalcogenide waveguide.

    Science.gov (United States)

    Tan, Kang; Marpaung, David; Pant, Ravi; Gao, Feng; Li, Enbang; Wang, Jian; Choi, Duk-Yong; Madden, Steve; Luther-Davies, Barry; Sun, Junqiang; Eggleton, Benjamin J

    2013-01-28

    We report a photonic-chip-based scheme for all-optical ultra-wideband (UWB) pulse generation using a novel all-optical differentiator that exploits cross-phase modulation and birefringence in an As₂S₃ chalcogenide rib waveguide. Polarity-switchable UWB monocycles and doublets were simultaneously obtained with single optical carrier operation. Moreover, transmission over 40-km fiber of the generated UWB doublets is demonstrated with good dispersion tolerance. These results indicate that the proposed approach has potential applications in multi-shape, multi-modulation and long-distance UWB-over-fiber communication systems.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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].

  7. 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

  8. 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.

  9. 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

  10. 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%

  11. Polarization entanglement generation at 1.5 um based on walk-off effect due to fiber birefringence

    CERN Document Server

    Zhou, Qiang; Wang, Pengxiang; Huang, Yidong; Peng, Jiangde

    2012-01-01

    In this Letter, a linear scheme to generate polarization entanglement at 1.5 um based on commercial polarization maintained dispersion shifted fiber (PM-DSF) is proposed. The birefringent walk-off effect of the pulsed pump light in the PM-DSF provides an effective way to suppress the vector scattering processes of spontaneous four wave mixing. A 90 degree offset of fiber polarization axes is introduced at the midpoint of the fiber to realize the quantum superposition of the two correlated photon states generated by the two scalar processes on different fiber polarization axes, leading to polarization entanglement generation. Experiments of the indistinguishable property on single side and two-photon interference in two non-orthogonal polarization bases are demonstrated. A two photon interference fringe visibility of 89\\pm3% is achieved without subtracting the background counts, demonstrating its great potential in developing highly efficient and stable fiber based polarization-entangled quantum light source a...

  12. 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.

  13. 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.

  14. A novel fiber-laser-based fiber Bragg grating strain sensor with high-birefringence Sagnac fiber loop mirror

    Institute of Scientific and Technical Information of China (English)

    Ou Xu; Shaohua Lu; Suchun Feng; Shuisheng Jian

    2008-01-01

    A novel fiber-laser-based strain sensor is proposed and experimentally demonstrated. The laser cavity is composed of a high-birefringence Sagnac fiber loop mirror (HiBi-SFLM) and a fiher Bragg grating (FBG) which also acts as a strain-sensing element. In the linear region of the HiBi-SFI,M reflection spectrum, when the strain applied on the FBG makes the Bragg grating wavelength shift,, the laser output power changes due to reflectivity variation of the HiBi-SFLM. Experimental results show that the laser output power varies ahnost linearly with the applied strain. The measurement of the output power can be performed by a conventional photo-detector.

  15. 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.

  16. 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.

  17. PCF Structure with Circular Air Hole and Square Lattice and its High Birefringence and Lower Zero Dispersion Behavior

    Directory of Open Access Journals (Sweden)

    Pranaw Kumar

    2013-01-01

    Full Text Available In this paper a square lattice Photonic Crystal Fiber (PCF with circular air hole has been designed and the numerical analysis reported a zero dispersion for one of the proposed structure. A very high Birefringence of the order of have been observed. Among all the structures proposed, two structures have shown both increment and decline in the value of confinement loss at the same interval of wavelength. It has also been shown the shifting of zero of dispersion wavelength toward lower wavelength range with increase in the number of circular air holes of large area compared to the number of circular air holes of smaller area. A Full- vector TM, FDTD method has been used

  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. A Note on the Analysis of Electrodynamic Fields Radiated by Time-Harmonic Sources Within Non-Birefringent Anisotropic Media

    CERN Document Server

    Sainath, Kamalesh

    2015-01-01

    We address a challenge concerning the spectral-domain-based analysis of electromagnetic fields produced by time-harmonic current sources within planar-layered media, which arises specifically when sources are embedded inside non-birefringent anisotropic medium (NBAM) layers. In NBAM, the highly symmetric permeability and permittivity tensors can induce directionally-dependent, but polarization independent, propagation properties supporting "degenerate" characteristic polarizations. That is to say, the considered NBAM support four linearly independent field polarization eigenvectors associated with only two (rather than four) unique, non-defective eigenvalues. We explain problems that can arise when the source(s) specifically reside within NBAM planar layers when using canonical field expressions as well as obtain alternative expressions, immune to such problems, that form the foundation for a robust eigenfunction-based analysis of electromagnetic radiation and scattering within planar-layered media.

  20. 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

  1. Entanglement networks of 1,2-polybutadiene crosslinked in states of strain. VII. Stress-birefringence relations. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kan, H.C.; Carpenter, R.L.; Ferry, J.D.

    1979-11-01

    Crosslinks are introduced by ..gamma.. irradiation into 1,2-polybutadiene while strained in uniaxial extension near T/sub g/ with stretch ratio lambda/sub 0/, thereby trapping a proportion of the entanglements originally present. The stress at any subsequent strain lambda is accurately given by the sum sigma/sub N/ + sigma/sub x/, where sigma/sub N/ is the stress contributed by a trapped entanglement network with lambda = 1 as reference and a Mooney-Rivlin stress-strain relation, and sigma/sub x/ is that contributed by a crosslink network with lambda = lambda/sub 0/ as reference and neo-Hookean stress-strain relation. The birefringence is accurately given as ..delta..n = C/sub N/sigma/sub N/ + C/sub x/sigma/sub x/, where the C's are the respective stress-optical coefficients. From measurements at lambda = lambda/sub 0/ where sigma/sub x/ = 0, C/sub N/ can be determined separately. For polymer with 88% 1,2-microstructure, C/sub N/ and C/sub x/ are nearly equal and independent of irradiation dose, though strongly dependent on temperature. For polymer with (95-96)% 1,2, C/sub N/ and C/sub x/ are different (even opposite in sign) and dependent on dose. This behavior is associated with a side reaction of cyclization by the ..gamma.. irradiation, which is inhibited by the 1,4 moiety in the polymer with lesser 1,2 content. It is responsible for residual birefringence in the state of ease (lambda = lambda/sub s/) where sigma/sub N/ = -sigma/sub x/ and the stress is zero.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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...

  15. 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

  16. 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.

  17. 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.

  18. Parametric approaches to micro-scale characterization of tissue volumes in vivo and ex vivo: Imaging microvasculature, attenuation, birefringence, and stiffness (Conference Presentation)

    Science.gov (United States)

    Sampson, David D.; Chin, Lixin; Gong, Peijun; Wijesinghe, Philip; Es'haghian, Shaghayegh; Allen, Wesley M.; Klyen, Blake R.; Kirk, Rodney W.; Kennedy, Brendan F.; McLaughlin, Robert A.

    2016-03-01

    INVITED TALK Advances in imaging tissue microstructure in living subjects, or in freshly excised tissue with minimum preparation and processing, are important for future diagnosis and surgical guidance in the clinical setting, particularly for application to cancer. Whilst microscopy methods continue to advance on the cellular scale and medical imaging is well established on the scale of the whole tumor or organ, it is attractive to consider imaging the tumor environment on the micro-scale, between that of cells and whole tissues. Such a scenario is ideally suited to optical coherence tomography (OCT), with the twin attractions of requiring little or no tissue preparation, and in vivo capability. OCT's intrinsic scattering contrast reveals many morphological features of tumors, but is frequently ineffective in revealing other important aspects, such as microvasculature, or in reliably distinguishing tumor from uninvolved stroma. To address these shortcomings, we are developing several advances on the basic OCT approach. We are exploring speckle fluctuations to image tissue microvasculature and we have been developing several parametric approaches to tissue micro-scale characterization. Our approaches extract, from a three-dimensional OCT data set, a two-dimensional image of an optical parameter, such as attenuation or birefringence, or a mechanical parameter, such as stiffness, that aids in characterizing the tissue. This latter method, termed optical coherence elastography, parallels developments in ultrasound and magnetic resonance imaging. Parametric imaging of birefringence and of stiffness both show promise in addressing the important issue of differentiating cancer from uninvolved stroma in breast tissue.

  19. 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.

  20. 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

  1. An astronomical search for evidence of new physics: Limits on gravity-induced birefringence from the magnetic white dwarf RE J0317-853

    CERN Document Server

    Preuss, Oliver; Solanki, Sami K; Jordan, Stefan

    2004-01-01

    The coupling of the electromagnetic field directly with gravitational gauge fields leads to new physical effects that can be tested using astronomical data. Here we consider a particular case for closer scrutiny, a specific nonminimal coupling of torsion to electromagnetism, which enters into a metric-affine geometry of space-time. We show that under the assumption of this nonminimal coupling, spacetime is birefringent in the presence of such a gravitational field. This leads to the depolarization of light emitted from extended astrophysical sources. We use polarimetric data of the magnetic white dwarf ${RE J0317-853}$ to set strong constraints on the essential coupling constant for this effect, giving $k^2 \\lsim (19 {m})^2 $.

  2. 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

  3. 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...

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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)

  10. Third order optical non-linear (Z-scan), birefringence, photoluminescence, mechanical and etching studies on melaminium levulinate monohydrate (MLM) single crystal for optical device applications

    Science.gov (United States)

    Sivakumar, N.; Anbalagan, G.

    2016-10-01

    Z-scan studies on the grown crystal was investigated by diode-pumped Nd; YAG laser. Nonlinear refractive index (n2) and third-order nonlinear optical susceptibility (χ3) values of MLM were found to be -1.0 × 10-8 cm2/W and 1.36 × 10-6 esu respectively. Powder X-ray diffraction analysis depicted that the crystal belongs to monoclinic system with space group P21/c. Birefringence study revealed the optical dispersion behavior of MLM crystal. Linear refractive index on (10-1) plane was measured by prism coupling technique and was estimated to be 1.4705. Hardness study was carried out along three different planes which exhibit hardness anisotropy of 41.11%. Meyer's index values of the grown crystal for the (10-1), (010) and (111) planes were found to be 2.39, 2.61 and 2.04 respectively. Etching studies on the prominent (10-1) growth plane was explained by two dimensional layer growth mechanisms. Photoluminescence study was performed on MLM crystal to explore its efficacy towards optical device fabrications.

  11. 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 .

  12. 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.

  13. Coherent Bremsstrahlung, Coherent Pair Production, Birefringence and Polarimetry in the 20-170 GeV energy range using aligned crystals

    CERN Document Server

    Apyan, A; Badelek, B; Ballestrero, S; Biino, C; Birol, I; Cenci, P; Connell, S H; Eichblatt, S; Fonseca, T; Freund, A; Gorini, B; Groess, R; Ispirian, K; Ketel, T; Kononets, Y V; López, A; Mangiarotti, A; Sellschop, J P Friedel; Shieh, M; Sona, P; Strakhovenko, V M; Uggerhøj, U; Uggerhøj, Erik; Van Rens, B; Velasco, M; Vilakazi, Z Z; Wessely, O; Ünel, G; Kononets, Yu V

    2008-01-01

    The processes of coherent bremsstrahlung (CB) and coherent pair production (CPP) based on aligned crystal targets have been studied in the energy range 20-170 GeV. The experimental arrangement allowed these phenomena as well as their polarization dependence to be evaluated under conditions where single-photon cross-sections could be measured. This proved very important as the theoretical description of CB and CPP is an area of active theoretical debate and development. The theoretical approach used in this paper predicts both the cross sections and polarization observables very well for the experimental conditions investigated, indicating that the understanding of CB and CPP is reliable up to energies of 170 GeV. A birefringence effect in CPP was studied and it was demonstrated this enabled new technologies for high energy photon beam optics, such as polarimeters (for both linear and circular polarization) and phase plates. We also present new results regarding the features of coherent high energy photon emis...

  14. Polarization splitter based on highly birefringent dual-core photonic crystal fibers%高双折射双芯光子晶体光纤偏振分束器

    Institute of Scientific and Technical Information of China (English)

    郭士亮; 黄惠; 童凯; 王志斌; 胡春海; 李志全

    2014-01-01

    Based on the birefringence effect, a novel duel- core photonic crystal fiber polarization beam splitter was proposed. The birefringence of the splitter was improved by introducing dual elliptical air holes into each fiber core of the rectangle lattice structure photonic crystal fiber. Using the full- vector finite element method (FEM), the impacts of structural parameters of duel- core photonic crystal fiber on birefringence and coupling length were analyzed. And the characteristics of the splitter, such as coupling length, extinction ratio and bandwidth, were investigated. Numerical simulation results demonstrate that the coupling length is decreased while the birefringence is increased by increasing the ellipticity, and the isolation of the polarization state can be achieved and the polarized light extinction ratio is -45.42 dB when the working wavelength and transfer- length of the fiber are 1.55μm and 282μm, respectively. Besides, the extinction ratio is less than - 10 dB when the bandwidth is 89 nm as well as the range of the wavelength is 1.507- 1.596μm.%设计了一种基于双折射效应的新型矩形纤芯光子晶体光纤偏振分束器,通过在矩形晶格结构的光子晶体光纤的每个纤芯中引入一对椭圆来增加结构的双折射。应用全矢量有限元法(FEM)分析了双芯光子晶体光纤中结构参数对双折射和耦合长度特性的影响,数值模拟了该偏振分束器的性能。结果表明:增大椭圆率可以在增大结构的双折射的同时减小耦合长度,并且该分束器在工作波长为1.55μm、传输长度为282μm的光纤中能够实现偏振状态的隔离,消光比达到最小值-45.42 dB,并且在1.507~1.596μm、带宽为89 nm的范围内消光比小于-10 dB。

  15. 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

  16. 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.

  17. Birefringence in quantum wells of heterostructures In0.68Al0.1Ga0.13As/In0.42Al0.22Ga0.24As/InP

    Science.gov (United States)

    Syrbu, N.; Dorogan, A.; Dorogan, V.; Zalamai, V.

    2015-06-01

    The polarization dependences of reflection and wavelength modulated reflection spectra of quantum wells In0.68Al0.1Ga0.13As/In0.42Al0.22Ga0.24As were investigated. Spectral dependences of refractive indices, extinction coefficients, real and imaginary parts of dielectric constants of quantum wells structures for different polarizations were calculated by the Kramers-Kronig analysis. A phenomenon of birefringence and an interference of polarized light waves in quantum wells were researched. The isotropic wavelength λ0 = 1.246 μm was found out. Interference spectra changes the density of fringes and refractive indices (Δni, ΔnKK = nP,P-nS,S) intersect zero axis at energy of isotropic wavelength (0.955 eV).

  18. Analysis of radius effect on optical rotation of birefringent crystal particles%双折射晶体微粒光致旋转受其半径影响分析

    Institute of Scientific and Technical Information of China (English)

    张景超; 朱艳英; 窦红星; 魏勇; 沈军峰; 姚远

    2012-01-01

    利用双折射晶体微粒在具有自旋角动量的光束作用下可产生围绕自身光轴旋转的特性,在光镊实验平台上实现了双折射晶体微粒的光致旋转.为了提高晶体微粒的旋转频率,从理论和实验上对双折射晶体微粒的旋转频率受其半径的影响进行了分析.用MATLAB模拟出CaCO3晶体微粒和SiO2晶体微粒的旋转频率与其半径的三次方成反比的关系曲线,并测得相应的实验关系曲线,其结果与理论分析相吻合.在相同的激光功率下,CaCO3晶体微粒的最高旋转频率可达15.1 Hz,SiO2晶体微粒的最高旋转频率可达11.4 Hz.该结论可用于光致旋转在实际应用中晶体微粒大小的选择和其旋转频率的优化控制.%The principle of optical rotation due to the transfer of spin angular momentum from light to particles was discussed by analyzing the interaction between beam of light and birefringent crystal particles. The optical rotation of birefringent crystal particles was realized by using the equipment of the optical tweezers in experiment. For increasing the rotation frequency of crystal particles, the relation between rotation frequency of crystal particles and radius was analyzed in the experiment and theory research. The relation curve between calcium carbonate and silicon dioxide particles' rotation frequency and radius was simulated with MATLAB, and the result showed that the rotation frequency was inversely proportional to the cube of radius, in addition, the experimental data was in agreement with the theoretical simulation. Rotation frequency was measured in experiment with the same laser power, the result showed the maximum frequency of calcium carbonate was 15.1 Hz, and the maximum frequency of silicon dioxide particles was 11.4 Hz. The rationality of the experiment was testified compared with theoretical analysis. The conclusion can be used to the choice of crystal particles and the optimization control of rotation frequency in

  19. 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.

  20. 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.

  1. 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.

  2. Birefringence of cellotape: Jones representation and experimental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Belendez, Augusto; Frances, Jorge; Neipp, Cristian [Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Senal, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain); Fernandez, Elena [Departamento de Optica, FarmacologIa y Anatomia, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)], E-mail: a.belendez@ua.es

    2010-05-15

    In this paper, we analyse a simple experiment to study the effects of polarized light. A simple optical system composed of a polarizer, a retarder (cellotape) and an analyser is used to study the effect on the polarization state of the light which impinges on the setup. The optical system is characterized by means of a Jones matrix, and a simple procedure based on Jones vectors is used to obtain an expression for the intensity after the light passes through the optical system. The light intensity is measured by a photodetector and the expression obtained theoretically is experimentally validated. By fitting the experimental intensity data, the value of the retardation introduced by the retarder can also be obtained.

  3. Gravitational birefringence of light in Robertson-Walker cosmologies

    CERN Document Server

    Duval, C

    2016-01-01

    The spacetime evolution of massless spinning particles in a Robertson-Walker background is derived using the deterministic system of equations of motion due to Papapetrou, Souriau and Saturnini. A numerical integration of this system of differential equations in the case of the standard model is performed. The deviation of the photon worldlines from the null geodesics is of the order of the wavelength. Perturbative solutions are also worked out in a more general case. An experimental measurement of this deviation would test the acceleration of our expanding universe.

  4. Birefringent Bragg Gratings in Highly-Nonlinear Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    Kevin Cook; John Canning; John Holdsworth

    2008-01-01

    Efficient writing of Bragg gratings in 12-ring highly-nonlinear photonic crystal fibers is described. Experimental and numerical investigations are performed to reveal the optimum angle for coupling UV writing light to the core. Furthermore, we show that the formation of a strongly briefringent grating is at a particular angle of orientation.

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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

    2016-08-01

    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.

  10. 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.

  11. 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.

  12. 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.

  13. 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 ...

  14. Light-induced circular birefringence in cyanoazobenzene side-chain liquid-crystalline polyester films

    DEFF Research Database (Denmark)

    Naydenova, I; Nikolova, L; Ramanujam, P.S.;

    1999-01-01

    degrees mu m(-1) at 633 nm and three to four times larger at 488 nm. The effect is explained through photoinduced changes in the structure of the polymer films due to reorientation of the rod-like chromophores and angular momentum transfer from the circularly polarized light to the azobenzene side chains....

  15. High-birefringence photonic crystal fiber polarization filter based on surface plasmon resonance.

    Science.gov (United States)

    An, Guowen; Li, Shuguang; Yan, Xin; Yuan, Zhenyu; Zhang, Xuenan

    2016-02-20

    In this paper, we designed a C2v-symmetry-structured photonic crystal fiber with triangular lattice and Au-filled air holes. The finite element method is used to analyze the dispersion and confinement loss characteristics of the core mode and the surface plasmon mode of the metal wire. In this work, we found that the positions of resonance peaks and the resonance strength of core mode and surface plasmon mode can be well adjusted by changing the pitch between the cladding air holes and the diameters of the air holes or metal wires around the core. By optimizing the parameters of the fiber structure, a polarization filter at the communication band is designed. At the wavelength of 1.31 μm, which is located in the communication band, the fundamental mode in X pol can be filtered with the diameter of the metal wire d(m)=1.2  μm. When d(m)=1.4  μm, the fundamental mode in Y pol can be filtered at the wavelength of 1.55 μm, which is also located in the communication band. Compared with the ordinary single-polarization and single-mode photonic crystal fiber, the fiber we proposed in this paper can selectively filter out the polarized light in one direction by adjusting the wire diameter. It is meaningful for the development of the polarization filter in the communication band.

  16. Femtosecond Nonlinear Birefringence and Dichroism in Au:TiO_2 Composite Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Au:TiO2 nanocomposite film was fabricated by rf-sputtering. Both real and imaginary parts of x(3) were investigated by optical Kerr effect and pump-probe methods with femtosecond pulse with values of about 10-8 esu.

  17. 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

  18. 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% ...

  19. 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.

  20. 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.

  1. 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.

  2. The optimum scheme of a static Fourier-transform spectrometer based on birefringent crystal

    Institute of Scientific and Technical Information of China (English)

    Dongqing Zhang(张冬青); Fuquan Wu(吴福全); Shuhai Fan(范树海)

    2003-01-01

    An optimum design of static Fourier-transform spectrometer based on Savert prisms is presented in this paper. A new method of increasing path difference and resolution of spectrometer is given. When the angle between the crystal optical axis of the first Savert prism and the incident interface is 58° and the angle between the crystal optical axis of the second Savert prism and the incident interface is 28°, the maximum path difference will be 0.63 mm, the maximum resolution will be 15.8 cm-1, and the whole field-of-view will reach 6°.

  3. 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...

  4. 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}

  5. 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.

  6. 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...

  7. 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...

  8. The use of birefringence for predicting the stiffness of injection molded polycarbonate discs

    NARCIS (Netherlands)

    Neves, N.M.; Pouzada, A.S.; Voerman, J.H.D.; Powell, P.C.

    1998-01-01

    Polycarbonate discs were injection molded with different sets of molding conditions. The parameters studied were the flow rate, melt- and mold-temperature. The discs were subjected to three point support flexural tests. Those tests are specially intended for injection molded discs because of their i

  9. Broadband tunable Raman soliton self-frequency shift to mid-infrared band in a highly birefringent microstructure fiber

    Science.gov (United States)

    Wei, Wang; Xin-Ying, Bi; Jun-Qi, Wang; Yu-Wei, Qu; Ying, Han; Gui-Yao, Zhou; Yue-Feng, Qi

    2016-07-01

    Raman soliton self-frequency shifted to mid-infrared band (λ > 2 μm) has been achieved in an air-silica microstructure fiber (MF). The MF used in our experiment has an elliptical core with diameters of 1.08 and 2.48 μm for fast and slow axis. Numerical simulation shows that each fundamental orthogonal polarization mode has two wide-spaced λ ZDW and the λ ZDW pairs located at 701/2110 nm and 755/2498 nm along the fast and slow axis, respectively. Using 810-nm Ti:sapphire femtosecond laser as pump, when the output power varies from 0.3 to 0.5 W, the furthest red-shift Raman solitons in both fast and slow axis shift from near-infrared band to mid-infrared band, reaching as far as 2030 and 2261 nm. Also, mid-infrared Raman solitons can always be generated for pump wavelength longer than 790 nm if output pump power reaches 0.5 W. Specifically, with pump power at 0.5 W, the mid-infrared soliton in slow axis shifts from 2001 to 2261 nm when the pump changes from 790 nm to 810 nm. This means only a 20 nm change of pump results in 260 nm tunability of a mid-infrared soliton. Project supported by the National Natural Science Foundation of China (Grant Nos. 61405172, 61405173, and 61275093), the Natural Science Foundation of Hebei Province, China (Grant No. F2014203194), the College Science Research Program of Hebei Province, China (Grant No. QN20131044), and the Program of Independent Research for the Young Teachers of Yanshan University of China (Grant No. 13LGB017).

  10. 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.

  11. 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.

  12. Dielectric and magnetic birefringence in low-chlorine-doped n-type Zn{sub 1-x}Mn{sub x}Se

    Energy Technology Data Exchange (ETDEWEB)

    Saenger, M.F.; Hofmann, T. [Department of Electrical Engineering, University of Nebraska-Lincoln (United States); Hetterich, M. [DFG Center for Functional Nanostructures, Karlsruhe Univ. (Germany). Inst. fuer Angewandte Physik; Kirby, R.D.; Sellmyer, D.J. [Department of Physics and Astronomy, University of Nebraska-Lincoln (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln (United States); Schubert, M. [Department of Electrical Engineering, University of Nebraska-Lincoln (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln (United States)

    2008-05-15

    Generalized spectroscopic ellipsometry over the spectral range from 1.24 to 3.34 eV is used to investigate a set of molecular beam epitaxy grown lowchlorine-doped n-type Zn{sub 1-x}Mn{sub x}Se films on (001)-oriented GaAs for x=0.0, 0.02, 0.14 and 0.28. We present evidence for intrinsic optical anisotropy in dependence of the Mn concentration caused by wurtzitestructure domain formation. We employ a previously established dielectric function model that accounts for band-gap transition energy splitting in cubic semiconductors [Phys. Rev. B 60, 16618 (1999)]. Room temperature magneto-optic generalized ellipsometry in the Kerrconfiguration reveals the sp-d exchange energy splitting parameters upon expanding our anisotropy model by inclusion of chiral spin-polarized band-to-band transition contributions. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  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. Dual-frequency single-axis laser using a lead lanthanum zirconate tantalate (PLZT) birefringent etalon for millimeter wave generation: beyond the standard limit of tunability.

    Science.gov (United States)

    Le Gouët, Julien; Morvan, Loïc; Alouini, Mehdi; Bourderionnet, Jérôme; Dolfi, Daniel; Huignard, Jean-Pierre

    2007-05-01

    We demonstrate the generation of optically carried, broadly tunable, millimeter-wave signals with a dual-frequency single-axis Nd:YAG laser. A frequency difference as high as 127 GHz is reached thanks to an intracavity electro-optically tunable etalon made of lead zirconate tantalate (PLZT) ceramic. We show that the available frequency range is actually limited by the bandwidth of the amplification medium, namely, far beyond the usually accepted free spectral range value in the case of a single-axis laser. Both coarse discrete and fine continuous tunabilities are obtained with the same voltage-controlled device, opening the way to widely tunable low-phase-noise optically carried submillimeter or even terahertz sources. PMID:17410245

  15. 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.

  16. Evidence for vacuum birefringence from the first optical polarimetry measurement of the isolated neutron star RX\\, J1856.5$-$3754

    CERN Document Server

    Mignani, R P; Caniulef, D Gonzalez; Taverna, R; Turolla, R; Zane, S; Wu, K

    2016-01-01

    The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields ($B\\approx 10^{13}$ G), radiation from these sources is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission. A large observed polarisation degree is, however, expected only if quantum-electrodynamics (QED) polarisation effects are present in the magnetised vacuum around the star. The detection of a strongly linearly polarised signal would therefore provide the first observational evidence of QED effects in the strong-field regime. While polarisation measurements in the soft X-rays are not feasible yet, optical polarisation measurements are within reach also for quite faint targets, like the M7 which have optical counterparts with magnitudes $\\approx 26$--$28$. Here, we report on the measurement of optical linear polarisation for the prototype...

  17. 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...

  18. 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)

  19. Design of birefringent prisms in differential interference contras t microscopy%微分干涉相衬显微镜中偏光棱镜设计

    Institute of Scientific and Technical Information of China (English)

    蔡昕; 徐毓娴; 张志利

    2001-01-01

    微分干涉相衬显微测量术在生物医学、材料科学等领域中有广泛应用,其中偏振分光棱镜设计是关键技术之一.对应用于微分干涉相衬显微系统中的偏振分光棱镜Nomarski棱镜的主要参数之间的关系进行分析,并做了设计计算,得出了一些有实用价值的结论,使Noma rski棱镜的设计更简便,有利于促进微分干涉相衬显微测量术在我国的推广应用.

  20. Measuring the Wavelength of a Diode Laser and the Birefringence of Mica: The Experimental Examination of the IPHO 40 Held in Mexico

    Science.gov (United States)

    Moran-Lopez, J. L.; Ortiz, M. E.; Rodriguez, L. F.; Romero-Rochin, V.

    2010-01-01

    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…

  1. 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

  2. Maslov shear-waveforms in highly anisotropic shales and implications for shear-wave splitting analyses; Formes d`onde transversales de Maslov dans les argiles fortement anisotropes et implications dans les analyses de birefringence des ondes transversales

    Energy Technology Data Exchange (ETDEWEB)

    Caddick, J. [Leeds Univ. (United Kingdom). Dept. of Earth Sciences; Kendall, J.M.; Raymer, D.G. [Western Geophysical, Middlesex (United Kingdom). Dept. of Earth Sciences

    1998-09-01

    Shales are the most common sedimentary rocks in hydrocarbon environments often forming the source rock and trapping rock for a reservoir. Due to the platy nature of the constituent grains, shales are commonly anisotropic. In this paper we calculate seismic waveforms for highly anisotropic shales using Maslow asymptotic theory (MAT). This theory is an extension of classical ray theory which provides valid waveforms in regions of caustics (wavefront folding) where ray theory amplitudes are unstable. Asymptotic ray theory (ART) is based on the Fermat or geometrical ray which connects the source and receiver. In contrast, the Maslov solution integrates the contributions from neighbouring non-Fermat rays. Ray-paths, travel-times, amplitudes and synthetic seismograms are presented for three highly anisotropic shales using a very simple 1D model comprised of an anisotropic shale overlying an isotropic shale. The ART waveforms fail to account for complex waveform effects due to triplications. In comparison, the MAT waveforms predict nonsingular amplitudes at wavefront cusps and it predicts the diffracted signals from these cusps. A Maslov solution which integrates ray contributions over a single slowness component will break down when rays focus in 3D (at a point rather than along a line). One of the tested shales shows such a point caustic and integration over 2 slowness components is required to remove the amplitude singularity. Finally, we examine the effects of wavefront triplications on Alford rotations which are used to estimate shear-wave splitting. In such cases, the rotation successfully finds the fast shear-wave polarization, but it can be unreliable in its estimate of the time separation. (authors) 21 refs.

  3. 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。

  4. 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...

  5. 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.

  6. 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)

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  8. Terahertz polarization conversion with quartz waveplate sets

    NARCIS (Netherlands)

    Kaveev, A. K.; Kropotov, G. I.; Tsygankova, E. V.; Tzibizov, I. A.; Ganichev, S. D.; Danilov, S. N.; Olbrich, P.; Zoth, C.; Kaveeva, E. G.; Zhdanov, A. I.; Ivanov, A. A.; Deyanov, R. Z.; Redlich, B.

    2013-01-01

    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 inte

  9. 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.

  10. 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.

  11. 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.

  12. Reactive mesogen photoalignment on photopolymerizable composite layer

    Science.gov (United States)

    Mahilny, U. V.; Stankevich, A. I.; Trofimova, A. V.

    2016-08-01

    The volume photoanisotropy (photoinduced birefringence) and surface photoanisotropy (LC photoalignment) of compositions of LC monomer - benzaldehyde polymer upon polarized UV radiation have been revealed and investigated. A high quality of photoalignment is confirmed by an extreme value of birefringence and low imperfection of phase plates fabricated on the basis of LC monomer on composite layer.

  13. Faraday effect based optical fiber current sensor for tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Aerssens, M. [Telecommunications and Electromagnetism Dept., Univ. of Mons, 33 Boulevard Dolez, B-7000 Mons (Belgium); Belgian Nuclear Research Center, Boeretang 200, B-2400 Mol (Belgium); Gusarov, A. [Belgian Nuclear Research Center, Boeretang 200, B-2400 Mol (Belgium); Brichard, B. [F4E, Barselona (Spain); Massaut, V. [Belgian Nuclear Research Center, Boeretang 200, B-2400 Mol (Belgium); Megret, P.; Wuilpart, M. [Telecommunications and Electromagnetism Dept., Univ. of Mons, 33 Boulevard Dolez, B-7000 Mons (Belgium)

    2011-07-01

    Fiber optical current sensor (FOCS) is a technique considered to be compatible with the ITER nuclear environment. FOCS principle is based on the magneto-optic Faraday effect that produces non-reciprocal circular birefringence when a magnetic field is applied in the propagation direction of the light beam. The magnetic field or the electrical current is deduced from the modification of the state of polarization of light. The linear birefringence of the fiber related with non-perfect manufacturing, temperature changes or stress constitute a parasitic effect that reduces the precision and sensitivity of FOCS. A two-pass optical scheme with a Faraday mirror at the end has been proposed to compensate the influence of linear birefringence. In this paper we perform a Stokes analysis of the two-pass optical scheme to highlight the fact that the linear birefringence is not compensated perfectly by the Faraday mirror when non-reciprocal birefringence such as Faraday effect is also present. (authors)

  14. Optical anisotropy in packed isotropic spherical particles: indication of nanometer scale anisotropy in packing structure.

    Science.gov (United States)

    Yamaguchi, Kohei; Inasawa, Susumu; Yamaguchi, Yukio

    2013-02-28

    We investigated the origin of birefringence in colloidal films of spherical silica particles. Although each particle is optically isotropic in shape, colloidal films formed by drop drying demonstrated birefringence. While periodic particle structures were observed in silica colloidal films, no regular pattern was found in blended films of silica and latex particles. However, since both films showed birefringence, regular film structure patterns were not required to exhibit birefringence. Instead, we propose that nanometer-scale film structure anisotropy causes birefringence. Due to capillary flow from the center to the edge of a cast suspension, particles are more tightly packed in the radial direction. Directional packing results in nanometer-scale anisotropy. The difference in the interparticle distance between radial and circumferential axes was estimated to be 10 nm at most. Nanometer-scale anisotropy in colloidal films and the subsequent optical properties are discussed.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Concerted spatial-frequency and polarization-phase filtering of laser images of polycrystalline networks of blood plasma smears

    Science.gov (United States)

    Ushenko, Yu A.

    2012-11-01

    The complex technique of concerted polarization-phase and spatial-frequency filtering of blood plasma laser images is suggested. The possibility of obtaining the coordinate distributions of phases of linearly and circularly birefringent protein networks of blood plasma separately is presented. The statistical (moments of the first to fourth orders) and scale self-similar (logarithmic dependences of power spectra) structure of phase maps of different types of birefringence of blood plasma of two groups of patients-healthy people (donors) and those suffering from rectal cancer-is investigated. The diagnostically sensitive parameters of a pathological change of the birefringence of blood plasma polycrystalline networks are determined. The effectiveness of this technique for detecting change in birefringence in the smears of other biological fluids in diagnosing the appearance of cholelithiasis (bile), operative differentiation of the acute and gangrenous appendicitis (exudate), and differentiation of inflammatory diseases of joints (synovial fluid) is shown.

  1. 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.

  2. Non-reciprocity of Faraday rotation in gyrotropic crystals

    OpenAIRE

    Vlokh R.; Adamenko D.

    2008-01-01

    It is shown that, under the conditions of coexisting natural optical activity and non-zero linear optical birefringence, reversal of the light wave vector sign can result in changing angle of Faraday rotation.

  3. 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.

  4. Polarimetric investigation of materials with both linear and circular anisotropy

    DEFF Research Database (Denmark)

    Naydenova, I.; Nikolova, L.; Todorov, T.;

    1997-01-01

    We investigate light propagation through materials with both linear and circular anisotropy and find the relation of the amplitude and polarization transfer functions to the four anisotropic characteristics: linear circular birefringence, and linear and circular dichroism. We determine these four...

  5. 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.

  6. 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

  7. 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

  8. Fiber-optic strain sensors for smart structures

    OpenAIRE

    KOSHIDE, Shinichi; 越出 慎一

    1997-01-01

    The first section of this report reviews the use of fiber-optic strain sensors in smart structures. Several types of fiber-optic sensor for strain and damage detection in structures are discussed including the high-birefringence polarimetric sensor, interferometric sensor, sensors which utilize scattered or attenuated light, and sensors which combine optical fibers and detectors such as a birefringent sensing cube or vibrating wire. Interferometric sensors are shown to be particularly suitabl...

  9. 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.

  10. 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...

  11. 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....

  12. 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...

  13. Skin collagen fiber molecular order: a pattern of distributional fiber orientation as assessed by optical anisotropy and image analysis.

    Directory of Open Access Journals (Sweden)

    Juliana Fulan Ribeiro

    Full Text Available BACKGROUND: Birefringence can reveal much of the morphology, molecular order, heterogeneity of fiber orientation, and nonlinear optical properties of biopolymers such as collagen. However, the detailed characterization of skin collagen fibers using optical anisotropy methods remains elusive. A clear understanding of collagen fiber organization in skin tissues may be important in the interpretation of their structural-functional relationships under normal and pathological conditions. In this study, fiber orientation in collagen bundles (CBs and their supramolecular organization were examined in rat skin using polarization microscopy and image analysis. METHODOLOGY/PRINCIPAL FINDINGS: Image variations with rotation of the microscope stage and selection of the in-depth focus plane were investigated in unstained sections of varying thicknesses from rat skin fragments. Total birefringence (image analysis and form and intrinsic birefringence (Sénarmont's method were estimated. Based on the birefringent images, CBs were found to contain intercrossing points with a twisted helical distribution of collagen fibers (chiral elements and frequently presented circular structures. Collagen fibers were observed to extend from the surface level to deeper planes, creating a 3D-network of oriented intertwined CBs. At least three levels of birefringent brilliance intensity were revealed by image analysis, indicating a heterogeneous spatial organization of the CBs. Slight differences in optical retardations were found for CBs immersed in some of the fluids used in a comparison of 170- and 240-day old rats. CONCLUSION/SIGNIFICANCE: Polarization microscopy studies provide detailed high-quality structural information on rat skin CBs. A 3D-network structure based on image analysis and birefringence compensation for collagen fibers is suggested for CBs. Form and intrinsic birefringence evaluation can reveal differences in the rat skin associated with age at the levels

  14. 一种Sagnac干涉仪结构的光子晶体光纤温度传感器%A Photonic Crystal Fiber Temperature Sensor Based on Sagnac Interferometer Structure

    Institute of Scientific and Technical Information of China (English)

    伍铁生; 王丽; 王哲; 刘玉敏; 胡署阳; 尹丽丹

    2012-01-01

    采用Sagnac干涉仪结构,设计了一种高双折射光子晶体光纤环镜温度传感器.光子晶体光纤温度稳定性好,通过向高双折射光子晶体光纤空气孔填充热光系数高的液体材料——乙醇,从而实现温度传感的目的.采用平面波展开法,分析了高双折射光子晶体光纤的双折射与传输波长和温度的关系.理论分析表明,填充乙醇后,高双折射光子晶体光纤的双折射随着传输波长和温度的增加而增加,且双折射与温度成线性关系.实验中将一段填充乙醇的高双折射光子晶体光纤与3 dB耦合器熔接制作成Sagnac干涉仪结构的光纤环镜,当温度从45℃升至80℃时,光谱仪上观察到凹点λi向短波方向漂移了309.280 nm,温度灵敏度高达8.837 nm/℃.%A highly birefringent photonic crystal fiber loop mirror temperature sensor based on Sagnac interferometer structure is designed. As the photonic crystal fiber has good temperature stability, in order to achieve the temperature sensing, ethanol which has a high thermal coefficient is filled into the air holes of the high birefringence photonic crystal fiber. Using plane wave expansion method, the relationship between birefringence of the highly birefringent photonic crystal fiber and transmission wavelength, and that between birefringence and temperature are analyzed. Theoretical analysis shows that: filled with ethanol, the birefringence of high birefringence photonic crystal fiber increases with the increase of the transmission wavelength and temperature, besides, there is a linear relationship between birefringence and temperature. In the experiment, a piece of high birefringence photonic crystal fiber filled with ethanol is welded with a 3 dB coupler to form a fiber loop mirror. When the temperature rises from 45℃ to 80 ℃ , the concave point drift of 309. 280 nm towards the short wavelength is observed on spectrum analyzer. The sensitivity is as high as 8. 837 nm/℃ .

  15. 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.

  16. 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

  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. 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

  19. Plasmonic metagratings for simultaneous determination of Stokes parameters

    CERN Document Server

    Pors, Anders; Bozhevolnyi, Sergey I

    2016-01-01

    Measuring light's state of polarization is an inherently difficult problem, since the phase information between orthogonal polarization states is typically lost in the detection process. In this work, we bring to the fore the equivalence between normalized Stokes parameters and diffraction contrasts in appropriately designed phase-gradient birefringent metasurfaces and introduce a concept of all-polarization birefringent metagratings. The metagrating, which consists of three interweaved metasurfaces, allows one to easily analyze an arbitrary state of light polarization by conducting simultaneous (i.e., parallel) measurements of the correspondent diffraction intensities that reveal immediately the Stokes parameters of the polarization state under examination. Based on plasmonic metasurfaces operating in reflection at the wavelength of 800 nm, we design and realize phase-gradient birefringent metasurfaces and the correspondent metagrating, while experimental characterization of the fabricated components convinc...

  20. 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 ...

  1. 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)].

  2. Dual-wavelength stable nanosecond pulses generation from cladding-pumped fiber laser

    Institute of Scientific and Technical Information of China (English)

    Shuling Hu; Jing Yu; Chunqing Gao; Guanghui Wei; Fuyun Lü

    2006-01-01

    In this paper, the generation of dual-wavelength stable nanosecond pulses by a laser diode pumped Ybdoped double-clad fiber laser is presented. In the experiment, the fiber laser with two-mirror cavity is approved which operates in a self-Q-switching regime. The Q-switching mechanism is based on stimulatedBrillouin scattering (SBS). When the pump power achieves the SBS threshold, the fiber laser changes from the start resonator to the SBS resonator. With different reflectivities of the second mirror, stable dual-wavelength pulses with the pulse width range from 10 ns to less than 2 ns are obtained. The resultwas explained theoretically by birefringency (including stochastic birefringency and bend birefringency).

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. Simple process for building large homogeneous adaptable retarders made from polymeric materials.

    Science.gov (United States)

    Delplancke, F; Sendrowicz, H; Bernaerd, R; Ebbeni, J

    1995-06-01

    A process for building large, homogeneous, adaptable retarders easily and at low cost is proposed and analyzed. This method is based on the properties of high polymers to present variable birefringence as a function of applied stresses and on the possibility of freezing these stresses inside the material by a thermal process. Various geometries for the applied forces make obtaining a large range of birefringence profiles possible. In the process that we describe composed bending leads to a linear birefringence profile. The superimposition of two pieces with identical profiles with opposite directions gives homogeneous constant retardation. This retardation can be adjusted by a relative displacement between the pieces. A precision of better than 1% over large areas (more than 3 cm in diameter) for a quarter-wave value has been obtained. The correct choice of material makes many applications possible with a large range of wavelengths.

  10. Great circle solution to polarization-based quantum communication (QC) in optical fiber

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Design of eight-mode polarization-maintaining few-mode fiber for multiple-input multiple-output-free spatial division multiplexing.

    Science.gov (United States)

    Wang, Lixian; LaRochelle, Sophie

    2015-12-15

    We propose a polarization-maintaining few-mode fiber (FMF) that features an elliptical ring shaped core with a high refractive index contrast ∼0.03 between the core and the cladding. This fiber design alleviates the usual trade-off between the number of guided modes and the achievable birefringence that is usually observed in conventional elliptical-core FMFs. Through numerical simulations, we show that this fiber design can support up to 10 guided vector modes over the entire C band while providing large birefringence. Except for the two fundamental modes, the eight higher-order vector modes are all separated from their adjacent modes by effective index differences >10⁻⁴, which is the typical birefringence value of single-mode polarization maintaining fibers. The designed fiber targets applications in spatial division multiplexing of optical channels, without multiple-input-multiple-output (MIMO) digital signal processing, for short-reach optical interconnects.

  12. 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.

  13. 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 ...

  14. 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.

  15. A new test of the Einstein equivalence principle and the isotropy of space

    CERN Document Server

    Haugan, Mark P; Haugan, Mark P; Kauffmann, Thierry F

    1995-01-01

    Recent research has established that nonsymmetric gravitation theories like Moffat's NGT predict that a gravitational field singles out an orthogonal pair of polarization states of light that propagate with different phase velocities. We show that a much wider class of nonmetric theories encompassed by the \\chi g formalism predict such violations of the Einstein equivalence principle. This gravity-induced birefringence of space implies that propagation through a gravitational field can alter the polarization of light. We use data from polarization measurements of extragalactic sources to constrain birefringence induced by the field of the Galaxy. Our new constraint is 10^8 times sharper than previous ones.

  16. 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.

  17. Lateral stress-induced propagation characteristics in photonic crystal fibres

    Institute of Scientific and Technical Information of China (English)

    Tian Hong-Da; Yu Zhong-Yuan; Han Li-Hong; Liu Yu-Min

    2009-01-01

    Using the finite element method, this paper investigates lateral stress-induced propagation characteristics in a pho-tonic crystal fibre of hexagonal symmetry. The results of simulation show the strong stress dependence of effective index of the fundamental guided mode, phase modal birefringence and confinement loss. It also finds that the contribution of the geometrical effect that is related only to deformation of the photonic crystal fibre and the stress-related contribution to phase modal birefringence and confinement loss are entirely different. Furthermore, polarization-dependent stress sensitivity of confinement loss is proposed in this paper.

  18. Orientational dynamics in dye-doped organic electro-optic materials

    DEFF Research Database (Denmark)

    Apitz, D.; Svanberg, C.; Jespersen, K.G.;

    2003-01-01

    The time dependent birefringence of polymer-based electro-optic materials is investigated using ellipsometry. We show that the birefringence after switching off the poling field does not depend only on the induced refractive index, but also on how that level was reached. The role of the poling...... voltage and poling time is discussed in turn-on and turn-off experiments and an original curve-fit function is introduced. We also propose a schematic model of the polymer dynamics in the system, which is consistent with complementary dielectric measurements. © 2003 American Institute of Physics. © 2003...

  19. Use of fiber helical coils to obtain polarization insensitive fiber devices

    Science.gov (United States)

    Tentori, Diana; Garcia-Weidner, A.; Rodriguez-Garcia, J. A.

    2016-09-01

    Using a new model for the description of the birefringence of a helical coil, it is shown that the birefringence effect on the signal polarization introduced by a fiber device can be canceled out by introducing two helical coils at the required orientation. Experimental results obtained using this modification in a polarization insensitive device (optical isolator) and in a non-polarization insensitive device working at two different wavelengths (wavelength division multiplexer) are presented and discussed. Such modified devices were used in the construction of an erbium-doped fiber amplifier (EDFA) with a full control of the input signal and pump states of polarization.

  20. 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.

  1. 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.

  2. 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.

  3. 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).

  4. 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.

  5. 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.

  6. 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....

  7. Anisotropic anti-rod dimer metamaterial film for terahertz polarization manipulation

    DEFF Research Database (Denmark)

    Zalkovskij, Maksim; Malureanu, Radu; Novitsky, Andrey;

    2012-01-01

    We demonstrate the concept of an anti-rod dimer planar metamaterial with strong birefringence and optical activity in the THz range. The retrieval of circular transmission components shows an asymmetric transmission effect for right-to-left and left-to-right polarization conversion.......We demonstrate the concept of an anti-rod dimer planar metamaterial with strong birefringence and optical activity in the THz range. The retrieval of circular transmission components shows an asymmetric transmission effect for right-to-left and left-to-right polarization conversion....

  8. 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

  9. 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.

  10. Characterization of Ultrafast Laser Pulses using a Low-dispersion Frequency Resolved Optical Grating Spectrometer

    Science.gov (United States)

    Whitelock, Hope; Bishop, Michael; Khosravi, Soroush; Obaid, Razib; Berrah, Nora

    2016-05-01

    A low dispersion frequency-resolved optical gating (FROG) spectrometer was designed to characterize ultrashort (recombines the pulses in a birefringent medium. The instrument detects a wavelength-sensitive change in polarization of the weak probe pulse in the presence of the stronger pump pulse inside the birefringent medium. Scanning the time delay between the two pulses and acquiring spectra allows for characterization of the frequency and time content of ultrafast laser pulses, that is needed for interpretation of experimental results obtained from these ultrafast laser systems. Funded by the DoE-BES, Grant No. DE-SC0012376.

  11. 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.

  12. 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

  13. Polymer-based photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Edrington, A.C.; Urbas, A.M.; Fink, Y.; Thomas, E.L. [Massachusetts Inst. of Tech., Cambridge (United States). Dept. of Materials Science and Engineering; DeRege, P. [Firmenich, Inc., Port Newark, NJ (United States); Chen, C.X.; Swager, T.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemistry; Hadjichristidis, N. [Athens Univ. (Greece). Dept. of Chemistry; Xenidou, M.; Fetters, L.J. [ExxonMobil Research Corp., Annandale, NJ (United States); Joannopoulos, J.D. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics

    2001-03-16

    The development of polymers as photonic crystals is highlighted, placing special emphasis on self-assembled block copolymers. 1D self-assembled multilayers as well as 2D and 3D self-assembled structures are examined, then intricate block polymer structures such as that shown in the Figure are discussed as are birefringent multilayer and elastomeric films. (orig.)

  14. 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.

  15. 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

  16. Measurement of the Cotton Mouton effect of water vapour

    CERN Document Server

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

    2013-01-01

    In this paper we report on a measurement of the Cotton Mouton effect of water vapour. Measurement performed at room temperature ($T=301$ K) with a wavelength of 1064 nm gave the value $\\Delta n_u = (6.67 \\pm 0.45) \\cdot 10^{-15}$ for the unit magnetic birefringence (1 T magnetic field and atmospheric pressure).

  17. Optical storage in azobenzene-containing epoxy polymers processed as Langmuir Blodgett films

    Energy Technology Data Exchange (ETDEWEB)

    Fernández, Raquel; Mondragon, Iñaki [‘Materials - Technologies’ Group, Department of Chemical and Environmental Engineering, Polytechnic School, Universidad País Vasco/Euskal Herriko Unibertsitatea, Pza Europa 1, 20018 Donostia-San Sebastián (Spain); Sanfelice, Rafaela C.; Pavinatto, Felippe J.; Oliveira, Osvaldo N. [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São Carlense, 400, Centro, CEP 13560-970, São Carlos (Brazil); Oyanguren, Patricia [Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata (Argentina); Galante, María J., E-mail: galant@fi.mdp.edu.ar [Institute of Materials Science and Technology (INTEMA), University of Mar del Plata and National Research Council (CONICET), J. B. Justo 4302, 7600 Mar del Plata (Argentina)

    2013-04-01

    In this study, azocopolymers containing different main-chain segments have been synthesized with diglycidyl ether of bisphenol A (DGEBA, DER 332, n = 0.03) and the azochromophore Disperse Orange 3 (DO3) cured with two monoamines, viz. benzylamine (BA) and m-toluidine (MT). The photoinduced birefringence was investigated in films produced with these azopolymers using the spin coating (SC) and Langmuir Blodgett (LB) techniques. In the LB films, birefringence increased with the content of azochromophore and the film thickness, as expected. The nanostructured nature of the LB films led to an enhanced birefringence and faster dynamics in the writing process, compared to the SC films. In summary, the combination of azocopolymers and the LB method may allow materials with tuned properties for various optical applications, including in biological systems were photoisomerization may be used to trigger actions such as drug delivery. Highlights: ► Langmuir Blodgett (LB) films of epoxy-based azopolymers were obtained and analyzed. ► Optical properties of LB and spin coated (SC) films were compared. ► Azo content, structure, laser power and number of layers were main factors studied. ► LB films had larger free volume for the azobenzenes isomerization than SC. ► LB films led to higher birefringence and faster dynamics compared to SC.

  18. Improvement of Response Performance of Liquid Crystal Optical Devices by using a Low Viscosity Component

    Institute of Scientific and Technical Information of China (English)

    PENG Zeng-Hui; LIU Yong-Gang; YAO Li-Shuang; CAO Zhao-Liang; MU Quan-Quan; HU Li-Fa; LU Xing-Hai; XUAN Li; ZHANG Zhi-Yong

    2011-01-01

    Difluorooxymethylene-bridged (CF2O) liquid crystal (LC) with low viscosity is prepared and used as a fast response LC material. When the material is mixed with isothiocyanato LCs with high birefringence, the visco-elastic coefficient of the mixture decreases evidently and, accordingly, the response performance increases. While the concentration of CF2O LCs is about 7%, the LC mixture approximately maintains high birefringence and exhibits a fastest response performance that is 14% higher than that of pure isothiocyanato LCs. Therefore, the LC material and mixing method could find useful applications in optical devices.%@@ Difluorooxymethylene-bridged(CF2O)liquid crystal(LC)with low viscosity is prepared and used as a fast response LC material.When the material is mixed with isothiocyanato LCs with high birefringence,the visco-elastic coefficient of the mixture decreases evidently and,accordingly,the response performance increases.While the concentration of CF2O LCs is about 7%,the LC mixture approximately maintains high birefringence and exhibits a fastest response performance that is 14%higher than that of pure isothiocyanato LCs.Therefore,the LC material and mixing method could find useful applications in optical devices.

  19. Orientation of the pigment molecules in the chloroplast

    NARCIS (Netherlands)

    Goedheer, J.C.

    1955-01-01

    Dichroism, absorption anisotropy, and anomal dispersion of birefringence were measured in the big lamellate chloroplasts of Mougeotia. The results of these measurements indicate a certain orientation of the chlorophyll molecules, and to a smaller extent, of the carotenoids in the chloroplast. In sp

  20. A study of airway smooth muscle in asthmatic and non-asthmatic airways using PS-OCT (Conference Presentation)

    Science.gov (United States)

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

    2016-03-01

    Present understanding of the pathophysiological mechanisms of asthma has been severely limited by the lack of an imaging modality capable of assessing airway conditions of asthma patients in vivo. Of particular interest is the role that airway smooth muscle (ASM) plays in the development of asthma and asthma related symptoms. With standard Optical Coherence Tomography (OCT), imaging ASM is often not possible due to poor structural contrast between the muscle and surrounding tissues. A potential solution to this problem is to utilize additional optical contrast factors intrinsic to the tissue, such as birefringence. Due to its highly ordered structure, ASM is strongly birefringent. Previously, we demonstrated that Polarization Sensitive OCT(PS-OCT) has the potential to be used to visualize ASM as well as easily segment it from the surrounding (weakly) birefringent tissue by exploiting a property which allows it to discriminate the orientation of birefringent fibers. We have already validated our technology with a substantial set of histological comparisons made against data obtained ex vivo. In this work we present a comprehensive comparison of ASM distributions in asthmatic and non-asthmatic human volunteers. By isolating the ASM we parameterize its distribution in terms of both thickness and band width, calculated volumetrically over centimeters of airway. Using this data we perform analyses of the asthmatic and non-asthmatic airways using a broad number and variety and subjects.

  1. A high definition Mueller polarimetric endoscope for tissue characterisation (Conference Presentation)

    Science.gov (United States)

    Qi, Ji; Elson, Daniel

    2016-03-01

    The mechanism of most medical endoscopes is based on the interaction between light and biological tissue, inclusive of absorption, elastic scattering and fluorescence. In essence, the metrics of those interactions are obtained from the fundamental properties of light as an electro-magnetic waves, namely, the radiation intensity and wavelength. As another fundamental property of light, polarisation can not only reveal tissue scattering and absorption information from a different perspective, but is also able to provide a fresh insight into directional tissue birefringence properties induced by birefringent compositions and anisotropic fibrous structures, such as collagen, elastin, muscle fibre, etc at the same time. Here we demonstrate a low cost high definition Muller polarimetric endoscope with minimal alteration of a rigid endoscope. By imaging birefringent tissue mimicking phantoms and a porcine bladder, we show that this novel endoscopic imaging modality is able to provide different information of interest from unpolarised endoscopic imaging, including linear depolarization, circular depolarization, birefringence, optic axis orientation and dichroism. This endoscope can potentially be employed for better tissue visualisation and benefit endoscopic investigations and intra-operative guidance.

  2. Second Harmonic Generation in CdTe Plate by Free Electron Laser

    Science.gov (United States)

    Yamauchi, Toshihiko; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki; Sawamura, Masaru; Hajima, Ryoichi; Shizuma, Toshiyuki; Hayakawa, Takehito

    2000-10-01

    The second harmonic generation (SHG) signal converted from the 22 μm input wavelength of free electron laser (FEL) is observed using a non-birefringent CdTe crystal. The conversion efficiency of SHG is experimentally obtained to be ˜3× 10-5%/(MWcm-2).

  3. Second harmonic generation in CdTe plate by free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Toshihiko; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Nishimori, Nobuyuki; Sawamura, Masaru; Hajima, Ryoichi; Shizuma, Toshiyuki; Hayakawa, Takehito [Division of Advanced Photon Research, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2000-10-01

    The second harmonic generation (SHG) signal converted from the 22 {mu}m input wavelength of free electron laser (FEL) is observed using a non-birefringent CdTe crystal. The conversion efficiency of SHG is experimentally obtained to be {approx}3 x 10{sup -5}% (MWcm{sup -2}). (author)

  4. Relativizing relativity

    OpenAIRE

    Svozil, Karl

    1998-01-01

    Special relativity theory is generalized to two or more ``maximal'' signalling speeds. This framework is discussed in three contexts: (i) as a scenario for superluminal signalling and motion, (ii) as the possibility of two or more ``light'' cones due to the a ``birefringent'' vaccum, and (iii) as a further extension of conventionality beyond synchrony.

  5. Study of optical properties and proteoglycan content of tendons by polarization sensitive optical coherence tomography

    Science.gov (United States)

    Yang, Ying; Rupani, Asha; Bagnaninchi, Pierre; Wimpenny, Ian; Weightman, Alan

    2012-08-01

    The highly orientated collagen fibers in tendons play a critical role for transferring tensile stress, and they demonstrate birefringent optical properties. However, the influence that proteoglycans (PGs) have on the optical properties of tendons is yet to be fully elucidated. PGs are the essential components of the tendon extracellular matrix; the changes in their quantities and compositions have been associated with tendinopathies. In this study, polarization sensitive optical coherence tomography (PS-OCT) has been used to reveal the relationship between PG content/location and birefringence properties of tendons. Fresh chicken tendons were imaged at regular intervals by PS-OCT and polarization light microscopy during the extraction of PGs, using guanidine hydrochloride (GuHCl). Complementary time-lapsed images taken from the two modalities mutually demonstrated that the extraction of PGs disturbed the local organization of collagen bundles. This corresponded with a decrease in birefringence and associated banding pattern observed by PS-OCT. Furthermore, this study revealed there was a higher concentration of PGs in the outer sheath region than in the fascicles, and therefore the change in birefringence was reduced when extraction was performed on unsheathed tendons. The results provide new insights of tendon structure and the role of PGs on the structural stability of tendons, which also demonstrates the great potential for using PS-OCT as a diagnostic tool to examine tendon pathology.

  6. Transparent alumina: A light scattering model

    NARCIS (Netherlands)

    Apetz, R.; Van Bruggen, P.B.

    2003-01-01

    A model based on Rayleigh-Gans-Debye light scattering theory has been developed to describe the light transmission properties of fine-grained, fully dense polycrystalline ceramics consisting of birefringent crystals. This model extends light transmission models based on geometrical optics, which are

  7. Photoinduced self-assembly of nanostructure in glass

    OpenAIRE

    Shimotsuma Y.; Asai T; Sakakura M.; Hirao K.; Miura K; Kazansky P. G.

    2013-01-01

    Ultrashort-pulsed laser direct writing can be useful for a 3D material processing. Especially the localized form-birefringence originated from self-assembled nanostructure in isotropic material (i.e. SiO2 and GeO2 glass) was demonstrated.

  8. Optical angular momentum conversion in a nanoslit

    NARCIS (Netherlands)

    Chimento, P.F.; Alkemade, P.F.A.; T Hooft, G.W.; Eliel, E.R.

    2012-01-01

    We demonstrate partial conversion of circularly polarized light into orbital angular momentum-carrying vortex light with opposite-handed circular polarization. This conversion is accomplished in a novel manner using the birefringent properties of a circular subwavelength slit in a thin metal film. O

  9. Response function for the characterization of photo-induced anisotropy in azobenzene containing polymers

    DEFF Research Database (Denmark)

    Sajti, S.; Kerekes, Á.; Ramanujam, P.S.;

    2002-01-01

    A response function is derived for the description of photo-induced birefringence and dichroism in case of materials where the underlying process is photo-isomerization. Our result explains the usefulness of the theoretical formulae derived earlier by Kakichashvili for photo-anisotropic materials...

  10. Recent Progress in Distributed Fiber Optic Sensors

    Directory of Open Access Journals (Sweden)

    Xiaoyi Bao

    2012-06-01

    Full Text Available Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices.

  11. Recent progress in distributed fiber optic sensors.

    Science.gov (United States)

    Bao, Xiaoyi; Chen, Liang

    2012-01-01

    Rayleigh, Brillouin and Raman scatterings in fibers result from the interaction of photons with local material characteristic features like density, temperature and strain. For example an acoustic/mechanical wave generates a dynamic density variation; such a variation may be affected by local temperature, strain, vibration and birefringence. By detecting changes in the amplitude, frequency and phase of light scattered along a fiber, one can realize a distributed fiber sensor for measuring localized temperature, strain, vibration and birefringence over lengths ranging from meters to one hundred kilometers. Such a measurement can be made in the time domain or frequency domain to resolve location information. With coherent detection of the scattered light one can observe changes in birefringence and beat length for fibers and devices. The progress on state of the art technology for sensing performance, in terms of spatial resolution and limitations on sensing length is reviewed. These distributed sensors can be used for disaster prevention in the civil structural monitoring of pipelines, bridges, dams and railroads. A sensor with centimeter spatial resolution and high precision measurement of temperature, strain, vibration and birefringence can find applications in aerospace smart structures, material processing, and the characterization of optical materials and devices. PMID:23012508

  12. Calibration of the optical torque wrench

    NARCIS (Netherlands)

    Pedaci, F.; Huang, Z.; Van Oene, M.; Dekker, N.H.

    2012-01-01

    The optical torque wrench is a laser trapping technique that expands the capability of standard optical tweezers to torque manipulation and measurement, using the laser linear polarization to orient tailored microscopic birefringent particles. The ability to measure torque of the order of kBT (∼4 pN

  13. Methacrylic azopolymers for holographic storage: A comparison among different polymer types

    DEFF Research Database (Denmark)

    Forcen, P.; Oriol, L.; Sanchez, C.;

    2007-01-01

    The photoinduced anisotropy and volume holographic storage in a series of polymers with different architectures and azo contents of 7% and 20% in weight have been investigated. Measurements of the birefringence (An) induced with nearly polarised 488 nm light show that for polymers with an azo con...... copolymers, as volume holographic storage material....

  14. Type II parametric downconversion in a poled fiber

    OpenAIRE

    Zhu, Eric Y.; Lee-Kim Koon, Edward A.; Qian, Lee-Kim; Helt, L. G.; Liscidini, Marco; Sipe, J. E.; Corbari, Costantino; Canagasabey, Albert; Ibsen, Morten; Kazansky, Peter G.

    2011-01-01

    We report photon-pair generation at the 1.5-?m telecom band via continuous-wave type-II parametric downconversion in a birefringent periodically-poled silica fiber. The time- and polarization-correlations of the downconverted light are examined

  15. Anisotropy of Wood in the Microwave Region

    Science.gov (United States)

    Ziherl, Sasa; Bajc, Jurij; Urankar, Bernarda; Cepic, Mojca

    2010-01-01

    Wood is transparent for microwaves and due to its anisotropic structure has anisotropic dielectric properties. A laboratory experiment that allows for the qualitative demonstration and quantitative measurements of linear dichroism and birefringence in the microwave region is presented. As the proposed experiments are based on the anisotropy (of…

  16. Second-order optical filter based on a mirrored gradient index lens.

    Science.gov (United States)

    Liang, W; Savchenkov, A A; Matsko, A B; Ilchenko, V S; Seidel, D; Maleki, L

    2010-07-15

    We demonstrate a second-order bandpass filter using a single gradient index lens (GRIN) coated with mirrors. The filter becomes possible because of the residual and externally introduced small birefringence of the GRIN lens material. We show that the filter function can be trimmed by mechanical strain of the lens. Applications of the filter in microwave photonics are discussed. PMID:20634829

  17. Polarization holographic gratings in side-chain azobenzene polyesters with linear and circular photoanisotropy

    DEFF Research Database (Denmark)

    Nikolova, Ludmila; Todorov, T.; Ivanov, Mario Tonev;

    1996-01-01

    We investigate thin phase polarization holographic gratings recorded with two waves with orthogonal linear polarizations in materials in which illumination with linearly/circularly polarized light gives rise to linear/circular birefringence. The theoretical analysis shows that the presence of cir...

  18. Morphology and epidermal thickness of normal skin imaged by optical coherence tomography

    DEFF Research Database (Denmark)

    Mogensen, Mette; Morsy, Hanan A.; Thrane, Lars;

    2008-01-01

    is to describe normal skin morphology using OCT and polarization-sensitive OCT (PS-OCT), which is a way of representing birefringent tissue such as collagen in OCT images. Anatomical locations in 20 healthy volunteers were imaged, and epidermal thickness (ET) was measured and compared to age, gender and skin...

  19. Temporally uncorrelated photon-pair generation by dual-pump four-wave mixing

    DEFF Research Database (Denmark)

    Christensen, Jesper Bjerge; McKinstrie, C. J.; Rottwitt, Karsten

    2016-01-01

    We study the preparation of heralded single-photon states using dual-pump spontaneous four-wave mixing. The dual-pump configuration, which in our case employs cross-polarized pumps, allows for a gradual variation of the nonlinear interaction strength enabled by a birefringence-induced walk...

  20. The Electro-Optic Beam Position Monitor

    CERN Document Server

    Doherty, James

    2013-01-01

    This reports outlines the development of a new ultra-wideband electro-optic beam position monitor (EO-BPM) for use in the Large Hadron Collider (LHC) which utilises birefringent crystals and the Pockels effect to monitor beam position. The physical principles behind the operation of the device and tested topology, which incorporates two Lithium Tantalate crystals, is discussed.

  1. Quadratic phase matching in slot waveguides

    OpenAIRE

    Di Falco, Andrea; Conti, Claudio; Assanto, Gaetano

    2006-01-01

    We analyze phase matching with reference to frequency doubling in nanosized quadratic waveguides encompassing form birefringence and supporting cross-polarized fundamental and second-harmonic modes. In an AlGaAs rod with an air void, we show that phase-matched second-harmonic generation could be achieved in a wide spectral range employing state-of-the-art nanotechnology.

  2. Holographic recording in thiophene-based polyester

    DEFF Research Database (Denmark)

    Matharu, Avtar Singh; Chambers-Asman, David; Jeeva, Shehzad;

    2008-01-01

    .4 I). The polyester ThPhAzoPol exhibits amorphous (Tg, 78.6 DC), crystalline and liquid crystalline character as evidenced by differential scanning calorimetry and thermal polarising microscopy. A grainy texture, which is thermally reversible, with increasing birefringence on cooling from...... are formed in addition as evidenced by atomic force microscopy....

  3. Imaging interferometry to measure surface rotation field

    DEFF Research Database (Denmark)

    Travaillot, Thomas; Dohn, Søren; Boisen, Anja;

    2013-01-01

    This paper describes a polarized-light imaging interferometer to measure the rotation field of reflecting surfaces. This setup is based on a homemade prism featuring a birefringence gradient. The arrangement is presented before focusing on the homemade prism and its manufacturing process. The dep...

  4. Comparison between coil and taper fibre-polarisers

    OpenAIRE

    Varnham, M.P.; Tarbox, E.J.; Payne, D. N.; Barlow, A.J.; Ragdale, C.M.; De Fornel, F.

    1984-01-01

    Experimental results are presented which compare the performance of both coil end taper polarisers made from high-birefringence fibre. Taper polarisers with 35dB extinction have been constructed, while coil polarisers have yielded up to 62dB

  5. A subwavelength slit as a quarter-wave retarder

    NARCIS (Netherlands)

    Chimento, P.F.; Kuzmin, N.V.; Bosman, J.; Alkemade, P.F.A.; T Hooft, G.W.; Eliel, E.R.

    2011-01-01

    We have experimentally studied the polarization-dependent transmission properties of a nanoslit in a gold film as a function of its width. The slit exhibits strong birefringence and dichroism. We find, surprisingly, that the transmission of the polarization parallel to the slit only disappears when

  6. Efficient Tunable Mid-Wave Infrared Laser from 2 μm Tm,Ho:YVO4 Pumped Gain-Switched Cr2+:ZnSe Laser

    Institute of Scientific and Technical Information of China (English)

    MENG Pei-Bei; YAO Bao-Quan; LI Gang; JU You-Lun; WANG Yue-Zhu

    2011-01-01

    An efficient mid-wave infrared gain-switched Cr2+ :ZnSe laser pumped by a 2.058μm Tm,Ho:YVO4 laser is reported. As much as 3.86 W output is achieved with the pump power of 13.4 W at pulse repetition frequency of 15 kHz, corresponding to the slope efficiency of 30.9%. With a quartz birefringent filter inserted in the laser cavity and by rotating the external angle of the quartz birefringent filter, wavelength tuning range nearly from 2453nm to 2508nm with 5nm linewidth (FWHM) is also obtained.%@@ An efficient mid-wave infrared gain-switched Cr2+ :ZnSe laser pumped by a 2.058μm Tm,Ho:YVO4 laser is reported.As much as 3.86 W output is achieved with the pump power of 13.4 W at puke repetition frequency of 15 kHz,corresponding to the slope efficiency of 30.9%.With a quartz birefringent filter inserted in the laser cavity and by rotating the external angle of the quartz birefringent filter,wavelength tuning range nearly from 2453nm to 2508nm with 5nm linewidth(FWHM) is also obtained.

  7. Formation of temperature fields in doped anisotropic crystals under spatially inhomogeneous light beams passing through them

    Energy Technology Data Exchange (ETDEWEB)

    Zaitseva, E. V.; Markelov, A. S.; Trushin, V. N., E-mail: trushin@phys.unn.ru; Chuprunov, E. V. [Nizhni Novgorod State University (Russian Federation)

    2013-12-15

    The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.

  8. Formation of temperature fields in doped anisotropic crystals under spatially inhomogeneous light beams passing through them

    Science.gov (United States)

    Zaitseva, E. V.; Markelov, A. S.; Trushin, V. N.; Chuprunov, E. V.

    2013-12-01

    The features of formation of thermal fields in potassium dihydrophosphate crystal doped with potassium permanganate under a 532-nm laser beam passing through it have been investigated. Data on the influence of birefringence on the temperature distribution in an anisotropic crystal whose surface is illuminated by a spatially modulated light beam are presented.

  9. Methacryluic Azopolymers for Holographic Storage: A Comparison among Different Polymer Types

    DEFF Research Database (Denmark)

    Forcén, Patricia; Oriol, Luis; Sánchez, Carlos;

    2007-01-01

    The photoinduced anisotropy and volume holographic storage in a series of polymers with different architectures and azo contents of 7% and 20% in weight have been investigated. Measurements of the birefringence (An) induced with im- early polarised 488 nm light show that for polymers with an azo ...

  10. Blazed vector gratings fabricated using photosensitive polymer liquid crystals and control of polarization diffraction

    Science.gov (United States)

    Ono, Hiroshi; Kuzuwata, Mitsuru; Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro

    2014-03-01

    The blazed vector grating possessing antisymmetric distributions of the birefringence were fabricated by exposing the line-focused linearly polarized ultraviolet light on the photosensitive polymer liquid crystals. The polarization states of the diffraction beams can be highly and widely controlled by designing the blazed structures, and the diffraction properties were well-explained by Jones calculus.

  11. System of polarization correlometry of biological liquids layers polycrystalline structure

    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

    A model of generalized optical anisotropy of human bile is suggested and a method of polarimetric of the module and phase Fourier of the image of the field of laser radiation is analytically substantiated, that is generated by the mechanisms of linear and circular birefringence of polycrystalline networks with a diagnosis and differentiation of cholelithiasis against a background of chronic cholecystitis.

  12. Diffraction from polarization holographic gratings with surface relief in side-chain azobenzene polyesters

    DEFF Research Database (Denmark)

    Naydenova, I; Nikolova, L; Todorov, T;

    1998-01-01

    We investigate the polarization properties of holographic gratings in side-chain azobenzene polyesters in which an anisotropic grating that is due to photoinduced linear and circular birefringence is recorded in the volume of the material and a relief grating appears on the surface. A theoretical...

  13. Controlling light with plasmonic multilayers

    DEFF Research Database (Denmark)

    Orlov, Alexey A.; Zhukovsky, Sergei; Iorsh, Ivan V.;

    2014-01-01

    A number of fundamental electromagnetic effects unique to the latter are identified and demonstrated. Examples include the evolution of isofrequency contour shape from elliptical to hyperbolic, all-angle negative refraction, and nonlocality-induced optical birefringence. Analysis of the underlying physical...

  14. Demonstration of frequency control and CW diode laser injection control of a titanium-doped sapphire ring laser with no internal optical elements

    Science.gov (United States)

    Bair, Clayton H.; Brockman, Philip; Hess, Robert V.; Modlin, Edward A.

    1988-01-01

    Theoretical and experimental frequency narrowing studies of a Ti:sapphire ring laser with no intracavity optical elements are reported. Frequency narrowing has been achieved using a birefringent filter between a partially reflecting reverse wave suppressor mirror and the ring cavity output mirror. Results of CW diode laser injection seeding are reported.

  15. Square shaped flat-top beam in refractive beam shapers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

    2015-08-01

    Lossless transformation of round Gaussian to square shaped flat-top collimated beam is important in building highpower solid state laser systems to improve optical pumping or amplification. There are industrial micromachining applications like scribing, display repair, which performance is improved when a square shaped spot with uniform intensity is created. Proved beam shaping solutions to these techniques are refractive field mapping beam shapers having some important features: flatness of output phase front, small output divergence, high transmittance, extended depth of field, operation with TEM00 and multimode lasers. Usual approach to design refractive beam shapers implies that input and output beams have round cross-section, therefore the only way to create a square shaped output beam is using a square mask, which leads to essential losses. When an input laser beam is linearly polarized it is suggested to generate square shaped flat-top output by applying beam shaper lenses from birefringent materials or by using additional birefringent components. Due to birefringence there is introduced phase retardation in beam parts and is realized a square shaped interference pattern at the beam shaper output. Realization of this approach requires small phase retardation, therefore weak birefringence effect is enough and birefringent optical components, operating in convergent or divergent beams, can be made from refractive materials, which crystal optical axis is parallel to optical axis of entire beam shaper optical system. There will be considered design features of beam shapers creating square shaped flat-top beams. Examples of real implementations and experimental results will be presented as well.

  16. High-resolution polarization sensitive OCT for ocular imaging in rodents

    Science.gov (United States)

    Fialová, Stanislava; Rauscher, Sabine; Gröger, Marion; Pircher, Michael; Hitzenberger, Christoph K.; Baumann, Bernhard

    2015-03-01

    A new high-resolution polarization sensitive optical coherence tomography system was developed for imaging rodent retina. Various light-tissue interactions such as birefringence and depolarization can change the polarization state of light. In the eye, there are several tissues that have these properties, for example retinal pigment epithelium (depolarization) and sclera (birefringence). These layers play key roles in diseases like age-related macular degeneration or glaucoma. Animal models are an important component for understanding disease pathogenesis. The gold standard for the evaluation of preclinical experiments is histology, which is an invasive and terminal procedure. Since OCT is non-invasive, it has the potential to be an alternative to histology with the benefit of long-term study of the disease progression in the same animal. In this study, a superluminescent diode with spectrum width 100 nm and mean wavelength 840 nm is used as a light source in order to enable high axial resolution. Spectrometers are custom built to enable high imaging speed that allows acquiring 3D data sets with 1024x200x1536 voxels in 3.44 s. From the acquired data, images displaying phase retardation induced by birefringence and orientation of birefringent axis were calculated. In first measurements, we were able to identify the RPE-choroid complex (depolarization effect) and the sclera (strong birefringence) in the retina of Long-Evans and Sprague-Dawley rats. Our preliminary results demonstrate the feasibility of the system for high speed/resolution imaging of the rodent retina. This is useful for longitudinal studies of disease models of retinal disease in rats and mice

  17. Frequency tuning of polarization oscillations in spin-polarized vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Lindemann, Markus; Pusch, Tobias; Michalzik, Rainer; Gerhardt, Nils C.; Hofmann, Martin R.

    2016-04-01

    Controlling the coupled spin-photon dynamics in vertical-cavity surface-emitting lasers (VCSELs) is an attractive opportunity to overcome the limitations of conventional, purely charge based semiconductor lasers. Such spin-controlled VCSELs (spin-VCSELs) offer several advantages, like reduced threshold, spin amplification and polarization control. Furthermore the coupling between carrier spin and light polarization bears the potential for ultrafast polarization dynamics. By injecting spin-polarized carriers, the complex polarization dynamics can be controlled and utilized for high-speed applications. Polarization oscillations as resonance oscillations of the coupled spin- photon system can be generated using pulsed spin injection, which can be much faster than the intensity dynamics in conventional devices. We already demonstrated that the oscillations can be switched in a controlled manner. These controllable polarization dynamics can be used for ultrafast polarization-based optical data communication. The polarization oscillation frequency and therefore the possible data transmission rate is assumed to be mainly determined by the birefringence-induced mode-splitting. This provides a direct tool to increase the polarization dynamics toward higher frequencies by adding a high amount of birefringence to the VCSEL structure. Using this technique, we could recently demonstrate experimentally a birefringence splitting of more than 250 GHz using mechanical strain. Here, we employ the well-known spin-flip model to investigate the tuning of the polarization oscillation frequency. The changing mechanical strain is represented by a linear birefringence sweep to values up to 80πGHz. The wide tuning range presented enables us to generate polarization oscillation frequencies exceeding the conventional intensity modulation frequency in the simulated device by far, mainly dependent on the birefringence in the cavity only.

  18. Fiber-optic parametric amplifiers: Their advantages and limitations

    Science.gov (United States)

    Yaman, Fatih

    Fiber-optic parametric amplifiers (FOPAs) can be used in lightwave systems for several signal-processing applications including optical amplification, phase conjugation, and wavelength conversion. In principle, FOPAs can provide high gain uniform over a wide wavelength range (> 100 nm). What is more, FOPAs add little noise to the amplified signal. FOPAs can have noise figure as low as 0 dB when operated in the phase-sensitive mode and 3 dB in the phase insensitive mode. However, in practice, these advantages of FOPAs are compromised. In this work, I investigate several factors that limit the performance of FOPAs, and propose practical schemes to minimize those limitations. FOPAs can provide a relatively large gain bandwidth because the gain spectrum of FOPAs is not determined by material resonances but by the phase-matching condition. For the same reason, FOPAs are very sensitive to perturbations stemming from fiber irregularities. One such irregularity is that fiber dispersion varies randomly along the fiber length. My numerical modeling showed that, because of such variations, FOPA gain spectrum cannot maintain its flatness and also that FOPA gain profile changes from one fiber to the other. Using stochastic methods, an analytic theory is developed that can predict an "average gain spectrum." This analytic theory can be used to show that flatness of FOPA gain is recovered at the expense of reducing the gain bandwidth. Another fiber irregularity that affects FOPA gain spectrum is the residual birefringence. During the fiber-drawing process, the cross section of fiber core inevitably deviates from perfect circular symmetry. As a result, all non-polarization maintaining fibers exhibit residual birefringence. Both the magnitude of birefringence and the direction of its principal axis vary along the fiber length as well as in time. Because of residual birefringence, state of polarizations of the propagating fields change randomly also. Since the underlying four

  19. Cognitive training transfer using a personal computer-based game: A close quarters battle case study

    Science.gov (United States)

    Woodman, Michael D.

    In this dissertation, liquid crystal (LC) materials and devices are investigated in order to meet the challenges for photonics and displays applications. We have studied three kinds of liquid crystal materials: positive dielectric anisotropic LCs, negative dielectric anisotropic LCs, and dual-frequency LCs. For the positive dielectric anisotropic LCs, we have developed some high birefringence isothiocyanato tolane LC compounds with birefringence ˜0.4, and super high birefringence isothiocyanato biphenyl-bistolane LC compounds with birefringence as high as ˜0.7. Moreover, we have studied the photostability of several high birefringence LC compounds, mixtures, and LC alignment layers in order to determine the failure mechanism concerning the lifetime of LC devices. Although cyano and isothiocyanato LC compounds have similar absorption peaks, the isothiocyanato compounds are more stable than their cyano counterparts under the same illumination conditions. This ultraviolet-durable performance of isothiocyanato compounds originates from its molecular structure and the delocalized electron distribution. We have investigated the alignment performance of negative dielectric anisotropic LCs in homeotropic (vertical aligned, VA) LC cell. Some (2, 3) laterally difluorinated biphenyls, terphenyls and tolanes are selected for this study. Due to the strong repulsive force between LCs and alignment layer, (2,3) laterally difluorinated terphenyls and tolanes do not align well in a VA cell resulting in a poor contrast ratio for the LC panel. We have developed a novel method to suppress the light leakage at dark state. By doping positive Deltaepsilon or non-polar LC compounds or mixtures into the host negative LC mixtures, the repulsive force is reduced and the cell exhibits an excellent dark state. In addition, these dopants increase the birefringence and reduce the viscosity of the host LCs which leads to a faster response time. In this dissertation, we investigate the

  20. Coherent control of optical activity and optical anisotropy of thin metamaterials

    CERN Document Server

    Mousavi, Seyedmohammad A; Shi, Jinhui; Zheludev, Nikolay I

    2013-01-01

    The future fibre optic communications network will rely on photons as carriers of information, which may be stored in intensity, polarization or phase of light. However, processing of such optical information usually relies on electronics. Aiming to avoid the conversion between optical and electronic signals, modulation of light with light based on optical nonlinearity has become a major research field, but real integrated all-optical systems face thermal management and energy challenges. On the other hand, it has recently been demonstrated that the interaction of two coherent light beams on a thin, lossy, linear material can lead to large and ultrafast intensity modulation at arbitrarily low power resulting from coherent absorption. Here we demonstrate that birefringence and optical activity (linear and circular birefringence and dichroism) of functional materials can be coherently controlled by placing a thin material slab into a standing wave formed by the signal and control waves. Efficient control of the...