Showing papers on "Optical polarization published in 1980"
TL;DR: In a memorable banquet speech at the Pittsburgh meeting on BL Lac objects (the only words spoken not faithfully reported in the proceedings) Ed Spiegel suggested the name "blazar" for this class of objects as mentioned in this paper.
Abstract: In bringing together the material for this review our attention was drawn repeatedly to the remarkably similar characteristics of virtually all strongly polarized extragalactic objects, which are found as the nuclei of giant elliptical galaxies or as quasi-stellar sources. These are violent variability, a compact, flat-spectrum radio source, and a very smooth continuum extending at least to 10/l. These properties are common to the polarized sources in BL Lac objects over a wide range of luminosity and to some QSOs and radio galaxies. In view of the similarities, which suggest a common process of energy release close to the central core of these objects, we will treat them all as a single group. In a memorable banquet speech at the Pittsburgh meeting on BL Lac objects (the only words spoken not faithfully reported in the proceedings) Ed Spiegel suggested the name "blazar" for this class of object. A combination ofBL Lac object and quasar, with a strong feeling of the characteristic violent optical flaring, blazar seems an excellent name, one which we will adopt throughout the review. As we shall discuss in Sections V and VI, blazars may not be a different type of object from most quasars or active elliptical galaxies. These normal objects may have jets whose emission is beamed by relativistic bulk motion, and show blazar characteristics only when pointed at us. In reviewing the observational data we will be especially conscious of properties that could help distinguish an isotropic source from a beamed one. The blazars form only a small portion of active extragalactic objects. Optical emission from most QSOs and Seyfert nuclei shows only very small
405 citations
TL;DR: In this article, the relativistic jet model was used to explain the association of OVVs with strong, variable radio sources, strong optical polarization, and continuity of the radio to optical spectra.
Abstract: The radio through optical, and possibly X-ray, emission of QSOs and active galactic nuclei is analytically interpreted in terms of a relativistic jet containing high-energy particles and a magnetic field. Parallel to the jet axis, a strong, compact radio source and strongly polarized radiation are detected, while larger viewing angles relative to the jet axis result in spectral dominance by the central region containing the 'energy machine' which drives the energy flux in the jet. It is shown that the relativistic jet model can explain the association of OVVs with strong, variable radio sources, strong optical polarization, and continuity of the radio to optical spectra.
171 citations
136 citations
73 citations
TL;DR: In this article, optical counterparts to the inner regions of the radio jets are seen in 3C 66 B and 3C 31, and upper limits are set for optical jets in the other two galaxies.
Abstract: Optical observations of the radio jet galaxies 3C 66 B, 3C 31, NGC 315, and 3C 449 are reported. Optical counterparts to the inner regions of the radio jets are seen in 3C 66 B and 3C 31, and upper limits are set for optical jets in the other two.
66 citations
TL;DR: In this article, the tuning characteristics of 633-nm internal mirror lasers with either natural Ne or 20-Ne were studied, and it was found that the tuning curve of a polarization signal is S-shaped for the natural Ne laser, whereas that of the intramode beat frequency is S -shaped for 20-ne laser.
Abstract: Tuning characteristics of power, intramode beat frequency, and polarization of 633-nm internal mirror lasers filled with natural Ne or 20Ne are studied. It is found that the tuning curve of a polarization signal is S-shaped for the natural Ne laser, whereas that of the intramode beat frequency is S-shaped for the 20Ne laser. The characteristic parameters of the tuning curve of the intramode beat frequency are determined. The axial modes of a 3He–20Ne laser are collapsed into one by a transverse magnetic field and frequency stabilized by cooling the laser tube with a fan to keep the intramode beat constant. Frequency fluctuation of 3 × 10−10 is obtained by the Allan variance analysis for the integration period range of 0.1–100 sec. Absolute accuracy and interinstrumental reproducibility of stabilized wavelengths can be expected for a 3He–20Ne transverse Zeeman laser stabilized at the central frequency of the intramode beat.
60 citations
TL;DR: The generation of the time-reversed replica of an incident monochromatic image-bearing optical beam that is nonuniformly polarized is demonstrated and sources of distortion in the vector replica are discussed using standard theory of nonlinear beam interaction.
Abstract: We demonstrate the generation of the time-reversed replica of an incident monochromatic image-bearing optical beam that is nonuniformly polarized. A form cf degenerate four-wave mixing in liquid CS2 of beams at 532 nm is employed. We discuss sources of distortion in the vector replica using standard theory of nonlinear beam interaction.
51 citations
TL;DR: The saddle-point method has been used to carry out the integration approximately and the formalism is derived for the case where the scattering molecules are embedded in an infinite dielectric cylinder.
Abstract: Fluorescent and Raman scattering by molecules embedded in dielectric particles is strongly dependent on the morphology and optical properties of the particle and the distribution of active molecules within the particle. In this paper, the formalism is derived for the case where the scattering molecules are embedded in an infinite dielectric cylinder. Analytical results for the scattered fields are given for arbitrary angles of incidence. The general results, which involve an integral and a sum, are rather lengthy. Accordingly, the saddle-point method has been used to carry out the integration approximately. Numerical results are given for perpendicular incidence and for observation in the plane perpendicular to the cylinder axis, for single dipoles variously located within the cylinder, and for a uniform distribution of isotropic incoherent dipoles. The angular distribution and polarization of the scattered irradiance depends sensitively upon cylinder radius and refractive index, so that this effect must be considered if inelastic scattering signals are to be used as a diagnostic tool.
44 citations
TL;DR: In this paper, the authors present a survey of the classical theory of the coherent emission of radiation in the optical and submillimetre range from a relativistic electron beam in a transverse, plane-polarized, spatially periodic magnetic field.
Abstract: In this paper we present a survey of the classical theory of the coherent emission of radiation in the optical and submillimetre range from a relativistic electron beam in a transverse, plane-polarized, spatially periodic magnetic field. Two kinds of lay-outs are proposed: the converter and the transverse optical klystron (TOK) in the reflex version.
34 citations
TL;DR: For nonnormal incidence angles, it has been shown that the polarization state may be controlled through the use of specially designed multilayer coatings.
Abstract: For nonnormal incidence angles, it has been shown that the polarization state may be controlled through the use of specially designed multilayer coatings. An optimization technique has been used to determine layer thicknesses for a coating design that produces a 90 degrees phase shift between the p- and s-polarization components over a wavelength range of Deltalambda/lambda(0) = +/-5% while maintaining high reflectivities for both components. A tolerance analysis indicates that the coating layers must be deposited within +/-1% to achieve a +/-3 degrees phase shift error over the spectral range of the design.
29 citations
TL;DR: In this article, the excited projectile state density matrix is derived from the impact-parameter version of the Oppenheimer-Brinkman-Kramers approximation for a one electron capture process from localized target states.
Abstract: The excited-projectile state density matrix is derived from the impact-parameter version of the Oppenheimer-Brinkman-Kramers approximation for a one electron-capture process from localized target states The result is used to determine the Stokes parameters of the emitted light General conditions for the production of atomic orientation are investigated and the connection to a recently published classical model is established Large values of atomic orientation and alignment are found for capture into a hydrogenic 2p state of the projectile A simple model for the beam-tilted-foil interaction yields a sinβ dependence of the circular polarization on the tilt angleβ Model calculations for beam-surface scattering show good agreement with experimental data for the relative Stokes parameters
TL;DR: In this paper, an instrument designed to record polarization in the region 120-150 nm of the solar spectrum was launched on the satellite Intercosmos-16, July 27, 1976.
Abstract: An instrument designed to record polarization in the region 120–150 nm of the solar spectrum was launched on the satellite Intercosmos-16, July 27, 1976. The aim was to search for resonance-line polarization that is caused by coherent scattering. Oblique reflections at gold- and aluminium-coated mirrors in the instrument were used to analyze the polarization. The average polarization of the Lα solar limb was found to be less than 1%. It is indicated how future improved VUV polarization measurements may be a diagnostic tool for chromospheric and coronal magnetic fields and for the three-dimensional geometry of the emitting structures.
01 Jan 1980
TL;DR: In this paper, the spectral properties of cometary dust grains were analyzed for models based on magnetite or olivine grain materials, with consideration given to the variation of thermal properties with particle radius and heliocentric distance.
Abstract: Observations of the sunlight scattered and thermal emission from cometary dust, which may be used to infer the physical properties of the dust grains, are reviewed. Consideration is given to the observed wavelength dependence of the scattered light from cometary coma and tails, the average scattering function of the dust grains, the average grain Bond albedo, the polarization of the scattered light, and grain temperatures deduced from thermal infrared emission. The thermal properties of dust grains are illustrated for models based on magnetite or olivine grain materials, with consideration given to the variation of thermal properties with particle radius and heliocentric distance. Comparison of the models with observations indicates that a disordered or amorphous olivine composition can give a reasonable fit to the data for appropriate grain sizes and temperatures. The observations acquired are noted to indicate an optically important particle size of 1 micron, with silicate particles not larger than a few microns usually present although pure silicate grains can not be responsible for the thermal emission, and the cometary dust grains are most likely not spherical. Further observations needed in the infrared are indicated.
TL;DR: In this article, the effective index approach to the theory of distributed feedback is applied to double heterostructure corrugated waveguides of practical interest and compared with other formulations.
Abstract: We refine the effective-index approach to the theory of distributed feedback so that it can be applied to double heterostructure corrugated waveguides of practical interest. We make comparisons with other formulations.
01 Jan 1980
TL;DR: In this article, a model for the amount of linearly polarized light reflected by the shiny leaves of such crops as wheat, corn, and sorghum is discussed, and the model adds to the understanding of the potential information content of scene polarization measurements acquired by future satellite sensor systems such as MRS.
Abstract: Sensors to remotely measure the linear polarization of ground scenes have been proposed for the Multispectral Resource Sampler (MRS), a satellite sensor system proposed to complement the Thematic Mapper. At present justification for a sensor on MRS to measure scene polarization is limited. This paper discusses a model for the amount of linearly polarized light reflected by the shiny leaves of such crops as wheat, corn, and sorghum. The theory demonstrates that, potentially, measurements of the linearly polarized light from a crop canopy may be used as an additional feature to discriminate between crops. Examination of the model suggests that, potentially, satellite polarization measurements may be used to monitor crop development stage, leaf water content, leaf area index, hail damage, and certain plant diseases. The model adds to the understanding of the potential information content of scene polarization measurements acquired by future satellite sensor systems such as MRS.
TL;DR: In this article, a light-reflection liquid-level sensor that uses a prismatic window in the side wall of the vessel whose liquid level is to be monitored is described and its design procedure is developed.
Abstract: When parallel-polarized light is reflected at an angle ? by the interface between two transparent media with refractive indices n and N, the interface reflectance is switched from 1 to 0 by varying the refractive index ratio N/n from sin ? to tan ?. This is the basis of a light-reflection liquid-level sensor that uses a prismatic window in the side wall of the vessel whose liquid level is to be monitored. Such a sensor is described and its design procedure is developed. Remote liquid-level telemetering is possible by using fiber optics to lead the light to and from this particular sensor.
TL;DR: In this paper, a simple expression is obtained by using the Stokes parameters and transforming the light propagation equations derived by the authors in a weakly inhomogeneous anisotropic active medium.
TL;DR: In this article, the emission line and continuum polarization of the Seyfert galaxies were studied and it was shown that the polarization of each galaxy is caused by an asymmetric dust envelope surrounding the nucleus.
Abstract: The paper presents intermediate resolution observations of the emission line and continuum polarization of the Seyfert galaxies Mrk 3, Mrk 231, NGC 3227, and NGC 3516. The polarization shows a strong wavelength dependence with the polarization increasing smoothly into the blue for each galaxy. This wavelength dependence, together with the presence of polarized H(alpha) emission, indicates that the polarization of each galaxy is caused by an asymmetric dust envelope surrounding the nucleus. Observations of the polarization of the /O III/ lambda 5007 emission in Mrk 3 and NGC 3227, and the polarization through the nonstellar Na ID line absorption in Mrk 231 are used to place constraints on the extent of the polarizing clouds in these galaxies. No polarization variability was detected with time-bases ranging from a few weeks to three years.
TL;DR: A review of theoretical and experimental investigations of the optical rectification effect (ORE) in nonlinear crystals is given in this article, focusing on aspects of using this effect for measurements of the nonlinear susceptibilities of crystals, measurement of the power, polarization, and profile of laser pulses, excitation of electromagnetic waves in waveguides and resonators, generation of infrared radiation, and nonlinear spectroscopy.
Abstract: A review is given of theoretical and experimental investigations of the optical rectification effect (ORE) in nonlinear crystals. Attention is focused on aspects of using this effect for measurements of the nonlinear susceptibilities of crystals, measurements of the power, polarization, and profile of laser pulses, excitation of electromagnetic waves in waveguides and resonators, generation of infrared radiation, and nonlinear spectroscopy. Further potential uses of the ORE are discussed.
TL;DR: Computations of the properties of sunlight scattered from models of the earth-atmosphere system are presented to show the effect of molecular anisotropy on the intensity, flux, and degree of polarization of the scattered light.
Abstract: Computations of the properties of sunlight scattered from models of the earth-atmosphere system are presented to show the effect of molecular anisotropy on the intensity, flux, and degree of polarization of the scattered light. The values of these parameters change significantly when the anisotropy factor is neglected in the molecular optical thickness and scattering phase matrix. However, if the Rayleigh scattering optical thickness is kept constant and the molecular anisotropy factor is included only in the Rayleigh phase matrix, the flux does not change, the intensity changes by a small amount, but the changes in the degree of polarization are still significant.
TL;DR: In this article, a novel class of frequency and polarization-modulated GaAs−AlxGa1−xAs double-heterojunction (DHEJ) lasers is described, formed by the monolithical integration of an optical amplifier, an electro-optic polarization modulator, and a polarizer.
Abstract: A novel class of frequency‐ and polarization‐modulated GaAs‐AlxGa1−xAs double‐heterojunction lasers is described. The lasers are formed by the monolithical integration of an optical amplifier, an electro‐optic polarization modulator, and a polarizer. Frequency modulation of 20 A/V and polarization rotation of 40° has been achieved by the linear electro‐optic effect.
TL;DR: In this article, an observation of variable linear polarization in the optical range in the unique radio and X-ray source SS 433, which is characterized by moving emission lines in its visible and near-IR spectra, is reported.
Abstract: Observations of variable linear polarization in the optical range in the unique radio and X-ray source SS 433, which is characterized by moving emission lines in its visible and near-IR spectra, are reported. The observations were made with an unfiltered GaAs photocathode covering the spectral region 3000-9000 A, with a passband characteristic wavelength near 7000 A. Measurements reveal the presence of both a long-term and a very short time-scale variation in linear polarization in the continuum and in H-alpha, which indicate that a substantial fraction of the polarization is intrinsic to SS 433 and not produced in the interstellar medium. It is suggested that the most likely source of polarization in the optical continuum is electron scattering, and constraints on models of SS 433 implied by the discovery of intrinsic polarization are considered.
TL;DR: In this paper, the resonance fluorescence due to intense laser fields from a Zeeman degenerate atom being perturbed by collisional interactions is calculated in the impact regime by using the quantumfluctuation-regression theorem.
Abstract: Resonance fluorescence due to intense laser fields from a Zeeman degenerate atom being perturbed by collisional interactions is calculated in the impact regime by using the quantum-fluctuation-regression theorem. Various interesting effects are found. For example, the scattered intensity spectrum for a J = 0 to J = 1 transition for polarization parallel to the laser polarization is essentially an asymmetric triplet, whereas for a perpendicular polarization due to collisions the spectrum is essentially a doublet (whose frequencies do not correspond with any of those of the triplet). Further, the width of the fluorescent component (whose frequency is close to the unperturbed frequency) actually decreases with increasing laser power.
TL;DR: An optical isolator for semiconductor lasers, consisting of a polarizer and a quarterwave plate, was investigated experimentally, assembled in a compact laser-to-fiber coupling module.
Abstract: An optical isolator for semiconductor lasers, consisting of a polarizer and a quarterwave plate, was investigated experimentally. It was assembled in a compact laser-to-fiber coupling module. Experiment showed forward loss of 1.15 dB, backward loss of 24.8 dB, and rotative tolerance of 2.4 deg for 1 dB down. The length of the module is 43.2 mm. The coupling efficiency to a graded-index multimode fiber is 37.5%. The extinction ratio is improved by 6.75 dB. The suppression effect on the influence of reflected light was investigated, using the assembled module.
01 Apr 1980
TL;DR: In this paper, the invariance of dispersion equations for electromagnetic wave in moving media is defined and discussed, and conditions for appearance of new wave modes are stated, and the question of velocity induced wave modes is considered.
Abstract: The derivation of dispersion equations for electromagnetic waves in moving media is considered. Absorption is included. It becomes clear that conduction current or polarization current models lead to identical dispersion equations in moving media. The invariance of dispersion equations is defined and discussed. The question of velocity induced wave modes in moving media is considered, and conditions for appearance of these new modes are stated.
TL;DR: In this article, the coupled mode theory is applied to noncollinear waves in planar dielectric waveguides and a theoretical study for deflection by a Bragg grating in the range of large incidence angles (10 to 75°).
TL;DR: In this paper, the Meudon and Pic-du-Midi regional polarization survey was used to detect the presence of a thin layer of small particles above the usual cloud layers.
Abstract: Previous photometric and polarimetric observations of Venus have indicated the presence of a thin layer of small particles above the usual cloud layers. We sensed some characteristics of this upper layer on the basis of the Meudon and Pic-du-Midi regional polarization survey, covering from 1950 to 1972. Optical thicknesses of the order of several percent with particle radii of around 0.2 ..mu..m are indicated. The refraction index is not known. Although this layer is apparently globally permanent, variations occur regionally and with time.
TL;DR: In this paper, the authors report observations of 39 extragalactic objects, using a new polarimeter at McDonald Observatory, most of which were made in January and June 1980.
Abstract: We report observations of 39 extragalactic objects, using a new polarimeter at McDonald Observatory. Most of the observations were made in January and June 1980. Some new BL Lac objects were found, and some of the previously known members of this class were also observed. Polarization exceeding 3--4 times the formal rms uncertainties was found in about ten QSO's. Rapid changes of polarization and/or position angle occurred in some of the BL Lacertae objects, usually with <0.1-mag change in the total light.