Showing papers on "Circular polarization published in 1972"
TL;DR: In this article, the transverse energy flux existing in total reflection of an elliptically polarized light beam was calculated by an energy-flux-conservation argument similar to Kristoffel's and to Renard's in their deduction of the longitudinal Goos-Hanchen shift, thus obtaining a formula different from those of the previous authors.
Abstract: Wiegrefe, Fedorov, Costa de Beauregard, and Schilling have discussed the transverse energy flux existing in total reflection of an elliptically polarized light beam, the latter two proposing formulas for the transverse shift of the reflected beam. We have calculated the transverse shift by an energy-flux-conservation argument similar to Kristoffel's and to Renard's in their deduction of the longitudinal Goos-H\"anchen shift, thus obtaining a formula different from those of the previous authors. We have also tested experimentally the existence of the transverse shift, in the optimal case of circular polarization and quasilimit total reflection, by using two slightly different multiplying procedures. Our measurements definitely vindicate our own formula for the transverse shift against both Costa de Beauregard's and Schilling's. The relevance of our results in connection with noncollinearity of velocity and momentum of the spinning photon inside the evanescent wave is very briefly discussed.
430 citations
TL;DR: In this paper, it was shown that for specific ratios of sound-to-light wavelengths, there is a substantially expanded angular range over which Bragg interaction can take place, allowing longer interaction lengths between light and sound, which greatly reduces the acoustic power required.
Abstract: Light deflector designs which use the anomalously low shear wave acoustic velocity and high acousto‐optic figure of merit in single‐crystal paratellurite, first proposed by Uchida and Ohmachi, have been made practical by exploiting this material's birefringence to circularly polarized light. Dixon's equations for Bragg interaction in birefringent materials are found to be equally applicable to optically active materials when linearly polarized propagation modes are replaced by circularly polarized modes. For specific ratios of sound‐to‐light wavelengths, there is a substantially expanded angular range over which Bragg interaction can take place. One effect of this increased range is to permit longer interaction lengths between light and sound, which greatly reduces the acoustic power required. In paratellurite, for visible light, this expanded range occurs for sound frequencies below 100 MHz, in the region of acceptable acoustic loss. Examples of possible designs include a deflector only 3×5×7 mm having a capacity of 500 linearly resolvable spots with a random access time of 10 μsec, with 50% of the incident light being deflected at 35‐mW acoustic power.
175 citations
TL;DR: In this article, the evolution of the polarization state of an electromagnetic wave propagating in a nonhomogeneous plasma with a sheared magnetic field was studied and a differential equation was given describing such evolution in the case of slowly varying plasma parameters.
Abstract: Studies the evolution of the polarization state of an electromagnetic wave propagating in a non-homogeneous plasma with a sheared magnetic field. A differential equation is given describing such evolution in the case of slowly varying plasma parameters. Assuming the model of a cold collisionless plasma one obtains an approximate solution giving the output polarization as a function of the input one and of the plasma parameters along the path. These results are applied to the case of a Tokamak; it is shown that in the some particular cases the output polarization is a relatively simple functional of the poloidal magnetic field. Therefore measurements of polarization can be used to determine the distribution of the poloidal field.
105 citations
TL;DR: In this paper, a light-water neutron trap in the reactor active zone as a γ-ray source was used to measure the circular polarization of the reaction n+p → d+ γ.
104 citations
TL;DR: In this article, a sensitive instrument for the measurement of the extent of circular polarization of light emitted by chiral molecules is described, in which the intensity of the circularly polarized component of the luminescence light is selectively modulated by an electro-optic or photoelastic light modulator, while the unpolarized component of light is unaffected.
Abstract: A sensitive instrument is described for the measurement of the extent of circular polarization of light emitted by chiral molecules. In this instrument the intensity of the circularly polarized component of the luminescence light is selectively modulated by an electro‐optic or photoelastic light modulator, while the unpolarized component of the luminescence is unaffected. The modulated light beam is detected by a photomultiplier and the ac component of the electric signal produced is amplified by a phase‐sensitive amplifier tuned to the modulation frequency. The light used for the excitation of the sample and the luminescence light are monochromated. An accessory is described which produces controlled mixtures of unpolarized and circularly polarized light and thus permits calibration of the output of the instrument in terms of the degree of circular polarization of the light under examination. Signal to noise ratios of 20 have been readily obtained with luminescence which is circularly polarized to an extent of 10−3 to 10−4.
88 citations
TL;DR: In this article, the polarization states of light incident on and emerging from an optical system are represented by complex numbers χ¯ and ξ¯, respectively, in two different planes.
Abstract: The polarization states of light incident on and emerging from an optical system are represented by complex numbers χ¯ and ξ¯, respectively, in two different planes. In this representation, the input–output transfer function ξ¯=f(χ¯) is a conformal bilinear transformation with coefficients given by the elements of the system’s Jones matrix. From the known properties of the bilinear transformation, important conclusions can be reached on the response of optical systems to incident light of all possible polarization forms. In addition, the analysis appears to have considerable potential in the synthesis of systems to effect a prescribed polarization transfer. As an example, the ellipsometer is analyzed by use of some of the ideas developed.
61 citations
TL;DR: In this paper, it was shown that the total cross sections for two-and three-photon ionization of a one-electron atom depend on the polarization of the incident light.
Abstract: We present a theoretical interpretation of an effect recently observed in two- and three-photon ionization of Cs. We show that the total cross sections for two- and three-photon ionization of a one-electron atom depend on the polarization of the incident light. Expressions are derived for the ratio of the cross section for circularly polarized light to that for linearly polarized, and their maximum values are obtained.
56 citations
TL;DR: In this article, it was shown that the wavelength of the circular polarization is sensitive to the imaginary part of the complex refractive index of the grain material, which provides an opportunity of investigating whether the grains are characteristically dielectric or metallic.
Abstract: This paper shows that optical observations of circular polarization produced by aligned interstellar grains could yield valuable information about the grain material. The interstellar medium is known to be linearly dichroic from observations of interstellar linear polarization. Since the same aligned grains make the medium linearly birefringent, a small component of circular polarization can result from incident linearly polarized light if the position angle of the linear polarization does not coincide with either principal axis of the medium. Calculations demonstrate that the wavelength of the circular polarization is sensitive to the imaginary part of the complex refractive index of the grain material. This provides an opportunity of investigating whether the grains are characteristically dielectric or metallic.
45 citations
TL;DR: In this paper, capture γ-ray circular polarization measurements on the Mn(n, γ), Ni(n and γ) reactions with polarized neutrons resulted in unambiguous spin assignments for 20 levels, 10 of which confirmed previous assignments.
44 citations
TL;DR: In this article, a sequence of harmonic resonances is observed for either sense of circular polarization, while the fundamental resonance is found for the polarization sensitive to electron. But these resonances are analyzed to originate from the electron Fermi surface centered at K-point in the Brillouin zone, of which large trigonal warping is deduced.
Abstract: Cyclotron resonances in single crystal graphite (SCG) and pyrolytic graphite (PG) have been investigated at about 23 and 69 GHz. A sequence of harmonic resonances is observed for either sense of circular polarization, while the fundamental resonance is found for the polarization sensitive to electron. These resonances are analysed to originate from the electron Fermi surface centered at K-point in the Brillouin zone, of which large trigonal warping is deduced. The observed cyclotron masses are m e / m o =0.058±0.001 (at 69.08 GHz) for SCG and 0.059±0.001 (at 68.01 GHz) for PG. Two kinds of additive structures in SCG, one being observed at 23 GHz and the other at 69 GHz, are discussed after the theoretical study by Uda, Ushio and Uemura of a nonlocal effect of the hole resonance and an electron-hole interaction, respectively. Each resonance field has the angular dependence of (cos θ) -1 , where θ is the angle between the applied magnetic field and the hexagonal axis.
39 citations
TL;DR: In this article, the crossover effect in the sunspot spectra was investigated and some properties of this effect in different spectral lines were investigated, including the anomalous splitting of the π-component of the Zeeman triplets.
Abstract: Two peculiarities of the magnetic splitting of lines in sunspot spectra have been investigated. The first one consists of the fact that in a rather small region of the penumbra, near the umbrapenumbra boundary, the π-component is absent in the spectra of one circular polarization while both σ-components are present. In the spectra of the opposite circular polarization, the σ-components are absent but the π-component is present. By analogy with the magnetic stars, in whose spectra such an effect was observed by Babcock, this phenomenon was called by us the ‘crossover effect’ in the sunspot spectra. Some properties of this effect in the different spectral lines were investigated. The nature of this effect is discussed. The second peculiarity consists of the anomalous splitting of the π-component of Zeeman triplets which are of the same and opposite signs in comparison with splitting of the σ-components. The different possibilities of explanation are discussed.
TL;DR: In this article, the polarization of photoelectrons is studied for atoms with one electron in the outermost shell in the state with well-defined total angular momentum j = l ± 1 2 and l > 0, exposed to circularly polarized ligth.
TL;DR: In this article, a study of the circular polarization structure of solar active regions has been made from data obtained at 9.5 mm, and the degree of polarization is about the same for both right and left circular components, and it ranges up to about 4%.
Abstract: A study of the circular polarization structure of solar active regions has been made from data obtained at 9.5 mm. All important active regions observed at 9.5 mm are bipolar in nature, the degree of polarization is about the same for both right and left circular components, and it ranges up to about 4%. These oppositely polarized components correspond with the Mt. Wilson magnetic regions of opposite polarity; the line of zero polarization delineates clearly the neutral line between the regions of opposite polarity on magnetograms. Unipolar regions in magnetograms also show up as unipolar regions at 9.5 mm. Magnetic fields as low as 5-10 G on magnetograms manifest as distinctly polarized regions on 9.5 mm maps.
TL;DR: In this paper, the authors reported observations of circular polarization of twilight of order 10−3, which is a large increase from the previous observation. But, the possibility of a substantially larger effect at twilight arises because there is no direct illumination, whereas in the daytime sky this mechanism should give only a small ellipticity.
Abstract: LINEAR polarization of clear daytime sky and twilight is produced by molecular (Rayleigh) scattering and aerosol (Mie) scattering, which predominates in the infrared. Incident linearly polarized light scattered by aerosols is in general elliptically polarized, whereas no ellipticity can arise from the molecular component1. The principal component of clear daytime sky arises from single scattering of unpolarized sunlight and is not elliptically polarized. However, whenever multiple scattering by the aerosol component is important, the strong linear polarization produced on the first scattering will lead to elliptical polarization from the second and subsequent scatterings. Although in the daytime sky this mechanism should give only a small ellipticity2 (10−5–10−3) the possibility of a substantially larger effect at twilight arises because there is no direct illumination. We report here observations of circular polarization of twilight of order 10−3.
TL;DR: In this paper, a search in many small regions of the Crab Nebula has resulted in the detection of a small component of circular polarization, and the variation of the sign and magnitude with position in the Nebula indicates that the polarization is of interstellar origin.
Abstract: A search in many small regions of the Crab Nebula has resulted in the detection of a small component of circular polarization. The variation of the sign and magnitude with position in the Nebula indicates that the polarization is of interstellar origin. On the basis of the polarity, strength, and colour dependence, it is concluded that the composition of the aligned grains causing this polarization is dielectric. Metallic particles are clearly ruled out.
TL;DR: In this paper, the authors studied the preferential emission of circularly polarized light of one sense over that of the opposite sense from chiral luminescent compounds. But the only CPL data available are of a few substances which exhibit an exceptionally high degree of circular polarization in their emitted light.
Abstract: Chiral compounds absorb circularly polarized light of opposite sense to different extents. This property, commonly known as circular dichroism, CD, is closely related to the optical rotatory dispersion of the compound under study, and has been extensively applied to the study of chiral compounds[1, 2]. On the other hand, very little information is available concerning the preferential emission of circularly polarized light of one sense over that of the opposite sense from chiral luminescent compounds. The scarcity of data about circularly polarized luminescence, CPL, is probably due to lack of suitable instrumentation for the measurement of small amounts of circularly polarized light present in a large background of unpolarized luminescence. Indeed, the only CPL data available are of a few substances which exhibit an exceptionally high degree of circular polarization in their emitted light [3, 4].
TL;DR: In this article, the authors give an interpretation to the fringes observed in holographic interferometry when plane-polarized light or circularly polarized light is utilized, and the obtained patterns are formed by the superposition of three families of fringes: the two families of absolute optical retardation and the family of relative retardation.
Abstract: The purpose of this paper is to give an interpretation to the fringes observed in holographic interferometry when plane-polarized light or circularly polarized light is utilized. It is shown that, when plane-polarized light is utilized and both the loaded and the unloaded states are considered, the obtained patterns are formed by the superposition of three families of fringes: the two families of absolute optical retardation and the family of relative retardation. The intensity distribution is also a function of the orientation of the plane of polarization, and along the points where the plane of polarization is parallel to one of the principal directions, only one of the families of absolute retardation is observed. By utilizing circularly polarized light, the dependence on the orientation of the principal axis is eliminated and patterns consisting of the superposition of the three above-mentioned families are obtained. If only the loaded state is considered, the holographic interferometer behaves as an ordinary polariscope with the reference beam playing the role of the analyzer. The relationships between the observed families are discussed. Examples of application to the disk and ring under diametral compression are also given.
TL;DR: In this article, a vibronic model is set up to study the strong orbital reduction of the excited state of the F -centee; Jahn-Teller coupling between electronic 2 p states and E g vibrational mode has been considered.
TL;DR: The significance of these data in colorimetry is discussed, and it is shown that serious errors may sometimes occur because of polarization in color-measuring instruments.
Abstract: Data are presented to show the effect of polarization of the incident beam on the reflectance factors of a number of reflecting materials in the visible spectrum. Data on the degree of polarization in the reflected radiation are also given. The significance of these data in colorimetry is discussed, and it is shown that serious errors may sometimes occur because of polarization in color-measuring instruments.
TL;DR: In this paper, observations of the white dwarf G195-19 made for over a year show that the periodic variation in circular polarization continues with constant frequency and amplitude; an accurate value of 13309 plus or minus 00004 days is obtained for the period.
Abstract: Observations of the white dwarf G195-19 made for over a year show that the periodic variation in circular polarization continues with constant frequency and amplitude; an accurate value of 13309 plus or minus 00004 days is obtained for the period While the variation in blue-green light is sinusoidal, extensive measurements in red light show an asymmetric curve, reaching a minimum about 6 hours earlier than in the blue-green
TL;DR: The experimental verification of the effect of the polarization of the electromagnetic wave on the linear transformation of waves in an inhomogeneous magneto-active plasma was carried out in this paper.
Abstract: The paper deals with the experimental verification of the effect of the polarization of the electromagnetic wave on the linear transformation of waves in an inhomogeneous magnetoactive plasma. Experiments were carried out in magnetic field satisfying conditionωce/ω>1, whereωce,ω are the electron cyclotron frequency and the frequency of the electromagnetic wave. The expressive dependence of the electromagnetic wave energy absorption on its polarization found experimentally is in excellent agreement with the theory.
Journal Article•
TL;DR: A review of observations of circular polarization of twilight performed with a polarimeter which uses an electronically switched Pockels cell operated as a reversible quarter-wave plate to convert circular into linear polarization is given in this paper.
Abstract: Review of observations of circular polarization of twilight performed with a polarimeter which uses an electronically switched Pockels cell operated as a reversible quarter-wave plate to convert circular into linear polarization. The latter was then analyzed by a Wollaston prism followed by two gallium-arsenide photomultipliers. The discovery of a definite natural circular polarization at twilight does suggest that, with increased observation precision, measurements of the small daylight component are possible. These could give useful information about particles in the atmosphere and be valuable in studies of meteorology and air pollution.