Showing papers on "Optical polarization published in 2000"
TL;DR: In this article, a novel radially polarized instead of a linearly polarized light annulus was proposed to reduce the focal area of a high aperture lens, which achieved an even smaller focal area, which is determined by the contour of the intensity distribution at half the maximum value.
808 citations
TL;DR: In this article, the authors reported an efficient electrical injection of spin-polarized carriers from a non-lattice-matched magnetic contact into a semiconductor heterostructure.
Abstract: We report efficient electrical injection of spin-polarized carriers from a non-lattice-matched magnetic contact into a semiconductor heterostructure. The semimagnetic semiconductor ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{Se}$ is used as a spin-injecting contact on a GaAs-based light-emitting diode. Spin-polarized electrons are electrically injected across the II-VI/III-V interface, where they radiatively recombine in a GaAs quantum well and emit circularly polarized light. An analysis of the optical polarization which includes quantum confinement effects yields a lower bound of 50% for the spin injection efficiency.
454 citations
TL;DR: In this article, the authors adopt an atomistic pseudopotential description of the electronic structure of self-assembled, lens-shaped InAs quantum dots within the ''linear combination of bulk bands'' method.
Abstract: We adopt an atomistic pseudopotential description of the electronic structure of self-assembled, lens-shaped InAs quantum dots within the ``linear combination of bulk bands'' method. We present a detailed comparison with experiment, including quantites such as the single-particle electron and hole energy level spacings, the excitonic band gap, the electron-electron, hole-hole, and electron-hole Coulomb energies and the optical polarization anisotropy. We find a generally good agreement, which is improved even further for a dot composition where some Ga has diffused into the dots.
321 citations
TL;DR: In this article, the phase-matching conditions of the propagating modes were analyzed and half of the reflection peaks were identified as the reflection to the same mode and the rest as reflection to neighboring modes, and the temperature dependence of each reflection peak is similar to that of a conventional Bragg grating in single-mode fiber.
Abstract: Bragg gratings in optical fibers in multimode propagation are investigated experimentally and theoretically. Bragg gratings formed in optical fibers in multimode propagation show multiple reflection peaks or multiple transmission dips in the reflection or transmission spectra, respectively. For standard graded-index multimode fiber, the number of reflection peaks of a Bragg grating depends on excitation condition of propagating modes. The number of reflection peaks of a Bragg grating at around 1.55 /spl mu/m is 19 for highly multimode excitation and 3-4 for lower order mode excitation. We analyze the phase-matching conditions of the propagating modes and identify half of the reflection peaks as the reflection to the same mode and the rest as the reflection to the neighboring modes. In dispersion-shifted fiber, a Bragg grating at around 0.8 /spl mu/m in three-mode propagation shows three reflection peaks in the reflection spectrum. The temperature dependence of each reflection peak is similar to that of a conventional Bragg grating in single-mode fiber. Polarization dependence measured on a Bragg grating in multimode graded-index fiber is negligible. An advantage of Bragg gratings in multimode fiber (MMF) and the applications are discussed.
267 citations
TL;DR: Mueller matrices provide a complete characterization of the optical polarization properties of biological tissue and revealed some tissue structures that are not perceptible with standard OCT.
Abstract: Mueller matrices provide a complete characterization of the optical polarization properties of biological tissue. A polarization-sensitive optical coherence tomography (OCT) system was built and used to investigate the optical polarization properties of biological tissues and other turbid media. The apparent degree of polarization (DOP) of the backscattered light was measured with both liquid and solid scattering samples. The DOP maintains the value of unity within the detectable depth for the solid sample, whereas the DOP decreases with the optical depth for the liquid sample. Two-dimensional depth-resolved images of both the Stokes vectors of the backscattered light and the full Mueller matrices of biological tissue were measured with this system. These polarization measurements revealed some tissue structures that are not perceptible with standard OCT.
258 citations
IBM1
TL;DR: In this paper, the authors developed a system for quantum key distribution (QKD) based on standard telecommunication lasers, detectors, and optical fiber, that passively compensates for time-dependent variations of the fiber-optic path due to stress, temperature changes, or birefringence.
Abstract: We have developed a system for quantum key distribution (QKD), based on standard telecommunication lasers, detectors, and optical fiber, that passively compensates for time-dependent variations of the fiber-optic path due to stress, temperature changes, or birefringence. This approach allows information encoded in phase shifts imposed on single-photon-level pulses to be accurately read out after transmission over many kilometers of uncontrolled fiber. Cooled InGaAs avalanche photodiodes, pulse-biased using a special noise canceling circuit, are used to detect single 1.31-/spl mu/m infrared photons with a high efficiency, low dark-count rate, and subnanosecond time resolution. A single optical fiber carries both the quantum information and precise 1.55 /spl mu/m timing pulses between the two end stations. Overall synchronization of end-station activities, public discussion of basis choices, error correction, and privacy amplification have all been implemented over a local area network (LAN). The system at present generates raw, error-corrected, and privacy-amplified key data at rates of /spl sim/1000, 600, and 200 bits/s, respectively, over a 10-km single-mode fiber link.
180 citations
TL;DR: A series of three perylene tetracarboxylic acid bisimide dyes 3a-c bearing phenoxy substituents at the four bay positions of the perylene core were synthesized and their complexation behavior to complementary ditopic dialkyl melamines was investigated in this article.
Abstract: A series of three perylene tetracarboxylic acid bisimide dyes 3a-c bearing phenoxy substituents at the four bay positions of the perylene core were synthesized and their complexation behavior to complementary ditopic dialkyl melamines 8a-c was investigated Binding constants and Gibbs binding energies for the hydrogen bonds between the imide and the complementary melamine moiety have been determined in several solvents by NMR and UV/Vis titration experiments with monotopic model compounds 5 and 9 The effects of the solvent polarity and specific solvent-solute interactions on the degree of polymerization of (3 x 8)n are discussed, and a general formula to estimate the chain length of [AA-BB]n nylon-type supramolecular polymers is derived In addition to the formation of a hydrogen-bonded supramolecular chain pi-pi interactions were observed for perylene bisimide-melamine assemblies 3b x 8b and 3b x 8c in aliphatic solvents The orthogonal nature of hydrogen bonding and pi-pi interactions leads to three-dimensional growth yielding large-sized aggregates already in dilute solution On suitable substrates, densely intertwined networks of nano- to mesoscopic strands are formed which have been investigated by electron microscopy, confocal fluorescence microscopy and optical polarization microscopy The high fluorescence and excellent photostability of these superstructures is promising for future studies on energy migration and artificial light harvesting at the nano- and mesoscopic length scale
175 citations
TL;DR: In this article, the authors considered the full radio flux density monitoring data between 8 and 90 GHz from the Michigan, Metsahovi, and Swedish-ESO Submillimeter Telescope AGN monitoring programs and found that the first of the two optical peaks is a thermal flare occurring in the vicinity of the black hole and the accretion disk, while the second one is a synchrotron flare originating in a shocked region down the jet.
Abstract: The BL Lac-type active galaxy OJ 287 exhibits a 12 year periodicity with a double-peaked maxima in its optical flux variations. Several models sought to explain this periodicity, the first one firmly established in any active galactic nucleus (AGN), as a result of the orbital motion of a pair of supermassive black holes. In one class of models the orientation of the jets changes in a regular manner, and the optical flaring is due to a consequent increase in the Doppler boosting factor. In another class of models the optical flaring reflects a true increase in luminosity, either due to an enhanced accretion during the pericenter passage or due to a collision between the secondary black hole and the accretion disk of the primary black hole. However, these models have been based solely on the optical data. Here we consider the full radio flux density monitoring data between 8 and 90 GHz from the Michigan, Metsahovi, and Swedish-ESO Submillimeter Telescope AGN monitoring programs. We find that the radio flux density and polarization data, as well as the optical polarization data, indicate that the first of the two optical peaks is a thermal flare occurring in the vicinity of the black hole and the accretion disk, while the second one is a synchrotron flare originating in a shocked region down the jet. None of the proposed binary black hole models for OJ 287 offers satisfactory explanations for these observations. We suggest a new scenario, in which a secondary black hole penetrates the accretion disk of the primary during the pericenter passage, causing a thermal flare visible only in the optical regime. The pericenter passage enhances accretion into the primary black hole, leading to increased jet flow and formation of shocks down the jet. These become visible as standard radio and optical synchrotron flares roughly a year after the pericenter passage and are identified with the second optical peaks. In addition to explaining the radio and the optical data, our model eliminates the need for a strong precession of the binary and for an ultramassive (≥1010 M☉) primary black hole. If our interpretation is correct, the next periodic optical flare, a thermal one, should occur around 2006 September 25. Nonthermal, simultaneous optical and radio flares should follow about a year later.
148 citations
TL;DR: In this article, an erbium-doped fiber laser was used for simultaneous multi-wavelength lasing, where the authors demonstrated that polarization hole burning can be enhanced by the changes of the light polarization states and bias current of optical MQW waveguide which serves as reflector in the laser.
106 citations
TL;DR: In this article, an adaptive polarization-mode dispersion (PMD) compensation system was developed to cancel the effects of first-order PMD by producing a complementary PMD vector in the receiver.
Abstract: An adaptive polarization-mode dispersion (PMD) compensation system has been developed to cancel the effects of first-order PMD by producing a complementary PMD vector in the receiver. Control parameters for the PMD compensation system comprised of a polarization controller and a PMD emulator are derived from the nonreturn-to-zero (NRZ) signal in the channel to be compensated. Estimates of the link's differential group delay (DGD) and principal states of polarization (PSPs) based on this signal are reliable when the signal power is equally split between the link's two PSP's; however this condition cannot be assumed. To meet this requirement, we scramble the state of polarization (SOP) of the input signal at a rate much greater than the response time of the PMD monitor signal so that each sample represents many different SOP alignments. This approach allows the effective cancellation of the first-order PMD effects within an optical fiber channel.
101 citations
TL;DR: The immunological methods provide results with little bias compared with HPLC and GC-MS, and the imprecision of the assays must be considered in the context of their intended use(s).
Abstract: Background: There is a need for systematic evaluation of methods before their release to the market. We addressed this problem in novel homocysteine assays as part of an European Demonstration Project involving six centers in four countries.
Methods: Two immunological methods for measurement of plasma total homocysteine (P-tHcy), the fluorescence polarization immunoassay (FPIA) and the enzyme immunoassay (EIA), were compared with two comparison methods, HPLC and gas chromatography–mass spectrometry (GC-MS). All laboratories performed the following procedures: ( a ) familiarization; ( b ) determination of linearity and precision by analyzing five plasma samples with interrelated concentrations for 20 days; ( c ) correlation using patients’ samples; and ( d ) assessment of long-term performance.
Results: Both immunological methods were linear for P-tHcy between 5 and 45 μmol/L. The intralaboratory imprecision (CV) was <5% for FPIA and <9% for EIA used with a sample processor. The bias was −2% to 3% for FPIA and 2–4% for EIA used with a sample processor.
Conclusions: The immunological methods provide results with little bias compared with HPLC and GC-MS. The imprecision of the assays must be considered in the context of their intended use(s).
TL;DR: An optical encryption system based entirely on the encryption of information using the phase component of a wavefront is presented and it is demonstrated that the direct pixel mapping approach provides a robust and simple architecture for optical encryption.
TL;DR: In this article, the authors have discovered a remarkable quasar, FIRST J101614.3+520916, whose optical spectrum shows unambiguous broad absorption features, while its double-lobed radio morphology and luminosity clearly indicate a classic Fanaroff-Riley type II radio source.
Abstract: We have discovered a remarkable quasar, FIRST J101614.3+520916, whose optical spectrum shows unambiguous broad absorption features, while its double-lobed radio morphology and luminosity clearly indicate a classic Fanaroff-Riley type II radio source. Its radio luminosity places it at the extreme of the recently established class of radio-loud broad absorption line quasars. Because of its hybrid nature we speculate that FIRST J101614.3+520916 is a typical FR II quasar that has been rejuvenated as a broad absorption line (BAL) quasar with a compact steep spectrum core. The direction of the jet axis of FIRST J101614.3+520916 can be estimated from its radio structure and optical brightness, indicating that we are viewing the system at a viewing angle of 40°. The position angles of the radio jet and optical polarization are not well aligned, differing by ~20°-30°. When combined with the evidence presented by Becker and coworkers for a sample of 29 BAL quasars showing that at least some BAL quasars are viewed along the jet axis, the implication is that no preferred viewing orientation is necessary to observe BAL systems in a quasar's spectrum. This, and the probable young nature of compact steep spectrum sources, leads naturally to the alternate hypothesis that BALs are an early stage in the lives of quasars.
TL;DR: In this article, a theoretical basis of polarization mode dispersion (PMD) equalizers based on the operator representation of PMD using Taylor's expansion is introduced, and two types of configuration of the PMD equalizers are derived as the inverse of diagonalization operators and delay time difference compensation.
Abstract: We introduce a theoretical basis of polarization mode dispersion (PMD) equalizers based on the operator representation of PMD using Taylor's expansion. The two types of configuration of PMD equalizers are derived as the inverse of diagonalization operators and delay time difference compensation. One is a type using physical rotation of quarter wave phase plates. The other is a type using variable phase shifters suitable for PLC integration. Waveform comparison algorithm was simulated to show the existence of multiple equivalent optimum points due to the symmetry and periodicity of optical circuits. The second order PMD equalization is discussed briefly on the case of cascading the first and the second PMD equalizing circuits with two different polarization state converters.
Patent•
30 Oct 2000
TL;DR: In this paper, a birefringent walk-off crystal has a first face adjacent to the focussing lens and a second face located at a focal plane of the lens and in contact with the ends of the second and third optical fibers.
Abstract: An optical polarization beam splitter comprises a first optical fiber having an end defining a first optical axis, a second optical fiber having an end defining a second optical axis, and a third optical fiber having an end defining a third optical axis parallel to and spaced apart from the second optical axis. A collimating lens is disposed along the first optical axis positioned to form a collimated optical beam from the first optical fiber. A focussing lens is disposed along a path of the collimated optical beam. A birefringent walk-off crystal has a first face adjacent to the focussing lens and a second face located at a focal plane of the focussing lens and in contact with the ends of the second and third optical fibers. The birefringent crystal is oriented such that and has a thickness between its first and second faces selected such that a first component of the optical beam having a first polarization exits the crystal at its second face and enters the end of the second optical fiber along the second optical axis and a second component of the optical beam having a second polarization orthogonal to the polarization of the first polarization exits the crystal at its second face and enters the end of the third optical fiber along the third optical axis.
TL;DR: In this paper, the authors have fabricated spin-polarized light-emitting diode structures via epitaxial regrowth of Zn1−xMnxSe on air-exposed surfaces of AlyGa1−yAs/GaAs quantum wells.
Abstract: We have fabricated spin-polarized light-emitting diode structures via epitaxial regrowth of Zn1−xMnxSe on air-exposed surfaces of AlyGa1−yAs/GaAs quantum wells No passivation procedures were used to protect or prepare the III–V surface The electroluminescence is strongly circularly polarized due to the electrical injection of spin-polarized electrons from the ZnMnSe contact into the GaAs quantum well An analysis of the optical polarization yields a lower bound of 65% for the spin injection efficiency These results demonstrate the robustness of the spin injection process in the diffusive transport regime, and attest to the practicality of manufacturing semiconductor-based spin injection devices
TL;DR: An optical encryption system that uses the polarization of light to encrypt a binary image and a random phase code (key to encrypted data) is experimentally demonstrated.
TL;DR: In this article, the authors measured the diffraction efficiency and analyzed the gratings characteristics for various writing beams polarizations in three polymers containing the same azo-dye, and revealed that the molecular mechanisms of holographic recording in the studied compounds are different.
TL;DR: In this article, the authors measured the photo-emission from a restricted section of a filament created in air as a result of propagation of a strong Ti:Sapphire laser pulse, the dependence of the propagation on the polarization (linear and circular) of the laser was studied.
TL;DR: In this paper, beat length and polarization mode dispersion (PMD) measurements performed on installed fibers were performed on three different kinds of fibers: standard step index, dispersion shifted and nonzero dispersion.
Abstract: We present beat length and polarization mode dispersion (PMD) measurements performed on installed fibers. Results regard three different kinds of fibers: standard step index, dispersion shifted and nonzero dispersion (NZD). After a historical comparison with standard differential group delay measurement collected four years ago on the same fibers, we perform a spatial-resolved measurement of the beat length by analyzing the state of polarization of the backscattered field. We compare PMD properties of different fibers and calculate the statistical distribution of the beat length. The differential group delay (DGD) and the beat length statistics depend strongly on fiber type and on fiber position along the link. The influence of the beat length on the DGD is also discussed.
TL;DR: In this paper, the influence of the shape of self-organized InAs/GaAs quantum dots on the electronic structure and optical properties of the quantum dots was considered and a valence force-field calculation of the inhomogeneous strain was performed.
Abstract: Recent experiments indicate that the shape of self-organized InAs quantum dots grown on GaAs [001] is an elongated pyramid with bounding facets corresponding to a family of four ${136}$ planes. This structure, which possesses ${C}_{2v}$ symmetry, is quite different from square-base pyramidal or lens geometries, which have been assumed in previous electronic structure calculations for this system. In this paper, we consider theoretically the influence of the ${136}$ shape on the electronic structure and optical properties of the quantum dots. We present a valence force-field calculation of the inhomogeneous strain and incorporate the results into an eight band $\stackrel{\ensuremath{\rightarrow}}{k}\ensuremath{\cdot}\stackrel{\ensuremath{\rightarrow}}{p}$ electronic structure calculation. The size dependence of the electronic structure is calculated and compared to experimental photoluminescence spectra. The effects of perturbations on the ${136}$ shape are also considered. Calculations based on the ${136}$ shape give good agreement with the observed level structure and optical polarization properties of self-organized InAs/GaAs quantum dots.
TL;DR: In this paper, it was shown that Solc filter structure under certain conditions of the alternating anisotropic layers acts as a perfect reflector at all angles, any polarization and over a wide spectral range thus can act as a photonic band gap structure.
TL;DR: In this paper, the experimental results for the polarizing properties of an optical coupler made of a single mode side-polished fiber and multimode metal-clad planar waveguide were reported.
TL;DR: In this paper, the authors investigated correlations between the polarimetric and photometric characteristics of a sample (496 objects) of young Herbig Ae/Be (HAEBE) stars and T Tauri (TT) stars.
Abstract: We present the results of the investigation of correlations between the polarimetric and photometric characteristics of a sample (496 objects) of young Herbig Ae/Be (HAEBE) stars and T Tauri (TT) stars. It is shown that, for 85% of the sample stars there is a gen- eral relation between the degree of optical polarization and the infrared colour index (V L)obs and the colour excess E(V L) due to the contribution of a circumstellar dust shell. Polarimetric data were also compared with the value of v sini to search for a possible correlation between the polarization and an inclination of circumstellar disks. Polarimetric data as well as IR excesses are considered and compared for dierent subgroups of young stars namely: HAEBE and TT stars with Algol{like minima of bright- ness (26 objects), Vega{type stars and post HAEBE stars (114 objects) and young solar{type stars (58 objects). For statistical purposes the data for young stars were com- pared with those collected for dierent groups of evolved objects such as: classical Be stars (300 objects), Mira Ceti stars (39 objects), early{type supergiants from the Serkowski et al. (1975) catalogue (120 objects) and main sequence (MS) stars within 50 pc from the Sun from the Leroy (1993) catalogue (68 objects). The value of polar- ization is discussed in context with the stages of evolution of circumstellar shells which were established by compari- son of spectral energy distribution in the far IR (using the IRAS data). It is shown that most young stars have sta- tistically larger value of polarization in comparison with the stars which are on a stage of evolution close to MS. We are able to contend that the changes in polarimetric behaviour of young stars are connected with evolution of their circumstellar shells.
TL;DR: Both immunoassays exhibited greatly improved throughput compared with the existing HPLC method, and the IMx assay had superior precision as well as the technological advantage of being completely automated.
Abstract: We evaluated the precision, linearity and accuracy of the Abbott IMx and Bio-Rad (Axis) homocysteine assays. Both assays make use of S-adenosyl-homocysteine hydrolase and excess adenosine, to convert homocysteine to S-adenosylhomocysteine (SAH). A monoclonal anti-SAH antibody is then used to quantify SAH. The IMx assay measures the fluorescence polarization of a conjugated SAH analogue for the final analytical step, whereas the Bio-Rad method uses a microplate enzyme immunoassay (EIA) employing an anti-mouse antibody peroxidase conjugate. The Abbott procedure is completely automated whereas the Bio-Rad EIA is performed manually. Between-run coefficient of variation using commercial controls was 2.6% at 7 micromol/L, 2.5% at 13 micromol/L and 1.7% at 24 micromol/L for the Abbott method, and 19.7% at 6.4 micromol/L, 15.9% at 11.0 micromol/L and 14.5% at 23.4 micromol/L for the Bio-Rad method. Both assays correlated well with a high-performance liquid chromatography (HPLC) procedure for homocysteine: Bio-Rad EIA = 1.03HPLC + 1.0 micromol/L, r=0.98, s(y/x)=0.51; Abbott IMx = 1.02HPLC + 0.7 micromol/L, r=0.99, s(y/x) = 0.33. Both methods were linear up to 50 micromol/L homocysteine. The IMx assay had superior precision as well as the technological advantage of being completely automated. Both immunoassays exhibited greatly improved throughput compared with our existing HPLC method.
TL;DR: In this paper, a coherent oscillation signal of the interlayer shearing phonon mode of highly oriented pyrolytic graphite was observed by means of femtosecond pump-probe experiment.
Abstract: We have observed a coherent oscillation signal of the interlayer shearing phonon mode of highly oriented pyrolytic graphite by means of femtosecond pump-probe experiment. The optical polarization dependence reveals a nontrivial phase shift between Rayleigh and Raman components. The detailed analysis of the phase shift clarifies that the Raman component mainly comes from the real part of the dielectric function. The excitation density dependence of the coherent phonon shows the same saturation behavior as that of the electronic response and the generation process of the coherent phonon is attributed to the real excitation of the $\ensuremath{\pi}\ensuremath{-}{\ensuremath{\pi}}^{*}$ transition.
TL;DR: In this paper, an optical polarization modulation technique was adapted to provide a simple, fast, and flexible method for studying the kinetics and growth characteristics of thin oxide layers, using Al2O3 as an example.
Abstract: An optical polarization modulation technique was adapted to provide a simple, fast, and flexible method for studying the kinetics and growth characteristics of thin oxide layers, using Al2O3 as an example. The optical technique allows precise determination of the amount of remaining metallic Al as a function of the initial Al thickness, while scanning a laser spot across the wedge. Optical data suggest that the oxide growth rate for the ultrathin layers may be dependent on the specific microstructure. In situ x-ray photoelectron spectroscopy performed on homogenous samples confirmed the interpretation of the optical results.
TL;DR: Analytically, the Abbott IMx method showed the best comparability with the in-house assay, but clinically, the three commercial methods were similar and did not distinguish cases from controls.
Abstract: Background: Hyperhomocysteinemia has been associated with coronary atherosclerosis in many, but not all, prospective and retrospective studies. Some on these inconsistencies may be attributed to methodological variabilities. Methods: In the present study, three newly commercially available assays and one in-house HPLC assay for total homocysteine (tHcy) were utilized in 99 subjects with angiographically documented atherosclerosis and in 91 community controls matched by age, gender, and smoking history. The in-house assay, a modified Fortin and Genest HPLC method, was compared with the Bio-Rad HPLC assay, the Abbott IMx ® fluorescence polarization immunoassay, and a Bio-Rad enzymelinked immunoassay (EIA) microtiter method. Results: Correlation coefficient values between the inhouse HPLC assay and the Bio-Rad HPLC, the Abbott IMx, and the Bio-Rad EIA assays were 0.95, 0.96 and 0.90, respectively. Although tHcy concentrations were higher in cases compared with controls by all four methods, the difference reached statistical significance only with the in-house HPLC procedure (median, 13.5 6 6.7 mmol/L in cases vs 10.9 6 4.8 mmol/L in controls; P <0.01, adjusting for covariates), where it was an independent predictor of case or control status, along with hypertension, total cholesterol, and triglycerides. The tHcy distributions in cases and controls demonstrated significant overlap. The number of atherosclerotic major coronary vessels was associated with significantly higher tHcy (P <0.01 for trend) in all four methods. Conclusions: The three commercial assays for tHcy differed in analytical and clinical performance. Analytically, the Abbott IMx method showed the best comparability with the in-house assay, but clinically, the three commercial methods were similar and did not distinguish cases from controls. © 2000 American Association for Clinical Chemistry
TL;DR: In this article, the authors presented optical polarimetry of the violently variable BL Lacertae object S5 0716+714, obtained over a three year period using the 6 m telescope at the Special Astrophysical Observatory in Russia.
Abstract: We present optical polarimetry of the violently variable BL Lacertae object S5 0716+714, obtained over a three year period using the 6 m telescope at the Special Astrophysical Observatory in Russia. The degree of polarization is high and variable throughout the observations. With a minimum time resolution of 1 minute, significant variations on a timescale of 10–15 minutes are observed. The variations are complex and not fully sampled by this data, but they are characterized by large amplitude changes on a timescale of about 1 day superposed on smooth variations with a timescale of about 1 week. Possible periods of 12.5, 2.5, and 0.14 days have been discovered. S5 0716+714 is a highly compact radio source with nonthermal emission observed across the electromagnetic spectrum out to gamma rays. The optical polarization variations are consistent with relativistically beamed synchrotron emission viewed at a very small angle to the line of sight.
Journal Article•
TL;DR: In this article, the properties of universal functions determining the probability of emission and absorption of photons from a plane-wave field in quantum-electrodynamic processes in the field of one and two light waves are derived.
Abstract: We study the properties of universal functions determining the probability of emission and absorption of photons from a plane-wave field in quantum-electrodynamic processes in the field of one and two light waves. Recurrence relations, summation formulas, and differential equations for these functions are derived. It is demonstrated that the emission (absorption) probability is highly sensitive to the polarizations of light waves, as well as to energy and kinematic variables.