Showing papers on "Optical polarization published in 1987"
TL;DR: In this article, the existence of the phase is attributed to the non-transitivity of Pancharatnam's connection between different states of polarization, and the precise relation is established using the algebra of spinors and 2 × 2 Hermitian matrices.
Abstract: In 1955 Pancharatnam showed that a cyclic change in the state of polarization of light is accompanied by a phase shift determined by the geometry of the cycle as represented on the Poincare sphere. The phase owes its existence to the non-transitivity of Pancharatnam's connection between different states of polarization. Using the algebra of spinors and 2 × 2 Hermitian matrices, the precise relation is established between Pancharatnam's phase and the recently discovered phase change for slowly cycled quantum systems. The polarization phase is an optical analogue of the Aharonov-Bohm effect. For slow changes of polarization, the connection leading to the phase is derived from Maxwell's equations for a twisted dielectric. Pancharatnam's phase is contrasted with the phase change of circularly polarized light whose direction is cycled (e.g. when guided in a coiled optical fibre).
874 citations
TL;DR: In this paper, an optical heterodyne receiver for DPSK signals with an arbitrary polarization state was proposed, where the received signal was split between two orthogonal polarization axes and the resulting two signals were demodulated.
Abstract: This paper describes an optical heterodyne receiver for DPSK signals which can receive an optical signal having an arbitrary polarization state. This is achieved by splitting the received signal between two orthogonal polarization axes and processing the resulting two signals as in a conventional DPSK heterodyne receiver. The sum of the two demodulated signals provides a baseband signal independent of the polarization state of the received optical signal. When the receiver noise is dominated by the shot noise of the photodetectors, the receiver provides a BER of 10-9for an average number of 22 photon/bit. In comparison, a conventional optical heterodyne receiver requires under the same noise condition 20 photon/bit to achieve the same BER for a received optical signal polarized along the polarization axis of the local optical signal.
271 citations
TL;DR: In this article, a novel polarization and wavelength independent digital electro-optic switch in Ti:LiNbO3 was proposed and demonstrated by a steplike response to the applied voltage.
Abstract: We propose and demonstrate a novel polarization‐ and wavelength‐independent digital electro‐optic switch in Ti:LiNbO3. This four‐port integrated optics switch is characterized by a steplike response to the applied voltage. Switching is achieved through adiabatic eigenmode transformation in an asymmetric waveguide junction. We demonstrate switching of both polarization components at two wavelengths (1.32 and 1.52 μm) with a crosstalk of −20 dB.
225 citations
TL;DR: In this paper, a theoretical treatment and experimental study of the phenomenon termed purely rotational coherence are presented, which arises from the thermal averaging of many single molecule coherences, with respect to their dependences on molecular parameters (rotational constants, transition dipole directions) and experimental parameters (polarization directions and temperature).
Abstract: In this and the accompanying paper we present a theoretical treatment and experimental study, respectively, of the phenomenon termed purely rotational coherence. This phenomenon has been demonstrated to be useful as a time domain means by which to obtain high resolution spectroscopic information on excited state rotational levels of large molecules [Felker et al., J. Phys. Chem. 90, 724 (1986); Baskin et al., J. Chem. Phys. 84, 4708 (1986)]. Here, the manifestations in temporally resolved, polarization-analyzed fluorescence of coherently prepared rotational levels in samples of isolated symmetric and asymmetric top molecules are considered. These manifestations, for reasonably large molecules at rotational temperatures characteristic of jet-cooled samples, take the form of polarization-dependent transients and recurrences with temporal widths of the order of tens of picoseconds or less. The transients, which arise from the thermal averaging of many single molecule coherences, are examined with respect to their dependences on molecular parameters (rotational constants, transition dipole directions) and experimental parameters (polarization directions and temperature). A physical picture of rotational coherence as a reflection of the time-dependent orientation of molecules in the sample is developed. And, the influence of rotational coherence in experiments designed to probe intramolecular energy flow is discussed. In the accompanying paper, we present experimental results for jet-cooled t-stilbene and anthracene. For t-stilbene we determine rotational constants for vibrational levels in the S1 electronic state (from the recurrences) and we monitor the trends in rotational coherence vs vibrational coherence as the total energy in the molecule increases.
189 citations
TL;DR: In this article, the effect of a linear random medium on the state of polarization of the transmitted light is investigated, and the connection between the Stokes vector formalism and the coherence or polarization matrix formalism is discussed.
Abstract: The effect of a linear random medium on the state of polarization of the transmitted light is investigated, and the connection between the Stokes vector formalism and the coherence or polarization matrix formalism is discussed. It is shown that an ensemble of Jones matrices corresponds to the Mueller matrix in general.
180 citations
TL;DR: The behavior of single solitons is similar to that of continuous waves, and the nonlinear effects make the fast mode unstable when the beat length between the modes is long, but nondispersive pulses can still propagate.
Abstract: We examine the propagation of solitons in the two linearly polarized modes of a birefringent fiber. The behavior of single solitons is similar to that of continuous waves, and the nonlinear effects make the fast mode unstable when the beat length between the modes is long. Even with the instability, nondispersive pulses can still propagate. High-order solitons break up and can transfer most of the energy into a single, highly compressed soliton.
180 citations
TL;DR: In this article, the authors applied Mueller matrix ellipsometry to assess the change in the state of polarization of a light beam that has double passed the ocular media and is scattered at the fundus of the human eye in vivo.
Abstract: We have applied Mueller matrix ellipsometry to assess the change in the state of polarization of a light beam that has double passed the ocular media and is scattered at the fundus of the human eye in vivo. At several positions in the pupil plane, which together cover the area of the dilated pupil, Mueller matrices are assessed. From them the magnitude of the retardation and the orientation of the eigenvector are calculated. The properties of the retardation process are surveyed by measuring the retardation along a horizontal meridian as a function of wavelength, density of visual pigment, and location of retinal fixation. Furthermore, photographs are taken from the polarization patterns on the iris with circularly polarized light. We posit that the cornea behaves as a biaxial crystal with its fastest principal axis normal to its surface and its slowest nasally downward. The retardation of light by a model eye with such a cornea is calculated, and the results are compared with the data.
166 citations
TL;DR: In this paper, the authors reported measurements of the general polarization of the Sun, both linear and circular, over the whole disk and over large sectors, at an absolute sensitivity level of ≲3×10−7, carried out during August-September 1986.
Abstract: The integrated light of the Sun, an essentially spherical star with only slight asymmetries (small oblateness, weak overall magnetic field), would normally be found to be unpolarized, as observed in broad spectral bands with common instrumental sensitivities, 10−4−10−5 fractional polarization1–4. Defining the Sun's intrinsic linear (LP) and circular (CP) polarizations down to much lower levels (10−7 or even 10−8) would have consequences not only in solar physics but in other areas, setting, for example, a new standard for stellar polarimetry. We report measurements of the general polarization of the Sun, both CP and LP, over the whole disk and over large sectors, at an absolute sensitivity level of ≲3×10−7, carried out during August–September 1986. Upper limits for the intrinsic whole-Sun LP from the best data (minimum Earth-atmospheric contamination) were 0.2×10−6 in the V (yellow) band and 0.8×10–6 in B (blue). Definite CP was discovered. (1) The north and south polar zones showed values of V (normalized or fractional CP) of −1 to −6×10−6 for the north, and 0 to +2×10−6 for the south zones. The spectral CP rises steeply toward the blue. (2) The whole disk had a net CP of −0.1 to −1.0×10−6 (from red to blue), negative as with the magnetically dominant north pole. The spectral dependence of the global broadband CP resembles that of sunspots5,6 and of local non-spot regions with magnetic flux tubes7.
153 citations
TL;DR: In this article, the probability density functions and lower-order moments of the four Stokes parameters are obtained as a function of the degree of polarization and the mean intensities of the two field components.
Abstract: The probability-density functions and lower-order moments of the four Stokes parameters are obtained as a function of the degree of polarization and the mean intensities of the two field components.
152 citations
TL;DR: A general design algorithm is presented for the multioutput polarization-encoded optical shadow-casting scheme and is used to determine the input pixel characteristics of a full adder and a full subtracter.
Abstract: A general design algorithm is presented for the multioutput polarization-encoded optical shadow-casting scheme. A set of POSC equations is obtained from the truth table of the desired logic unit and is solved in terms of four possible pixel characteristics (transparent, opaque, vertically polarized, and horizontally polarized) and four possible source characteristics (off, unpolarized, vertically polarized, and horizontally polarized). To demonstrate its feasibility, the algorithm is used to determine the input pixel characteristics of a full adder and a full subtracter.
96 citations
TL;DR: In this paper, the conditions required to achieve bistability in two-mode semiconductor laser via the nonlinearity associated with gain saturation are discussed, and the laser can be switched between the bistable states through coherent or incoherent optical control.
Abstract: The conditions required to achieve bistability in two‐mode semiconductor lasers via the nonlinearity associated with gain saturation are discussed. The laser can be switched between the bistable states through coherent or incoherent optical control. Wavelength bistability in such a laser is demonstrated experimentally.
TL;DR: In this article, the authors reviewed the progress in coherent optical fiber transmission systems from the viewpoint of regenerative repeater spacing and transmission data rate improvements. And they discussed future problems on the basis of the current state of the art.
Abstract: Essential technologies for developing coherent optical fiber transmission systems are reviewed from the viewpoint of regenerative repeater spacing and transmission data rate improvements. After describing the system features behind these advantages, recent progress in individual device and system technologies is delineated. Such progress includes frequency stabilization and linewidth reduction of semiconductor lasers, optical phase or frequency modulation, AM and FM noise suppression in coherent receivers, optical polarization stabilization and control in signal transmission, and optical direct amplification. Also described is progress in coherent optical transmission experiments carried out in many laboratories. Finally, future problems are discussed on the basis of the current state of the art.
TL;DR: In this paper, the authors derived conditions for the physical realizability of polarization matrices characterizing passive systems or scattering media, and showed that such matrices are physically realizable.
Abstract: We derive conditions for the physical realizability of polarization matrices characterizing passive systems or scattering media. By physically realizable, we mean that 0 g 1 where g ≡ (output intensity/input intensity). Using the singular-value decomposition of an arbitrary 2 × 2 complex-valued matrix, we prove that a Jones matrix T J is physically realizable if 0 det T J + T J 1. Consequently singular Jones matrices (i.e. det T J = 0) completely extinguish the output intensity irrespective of the input intensity because g ≡ 0. Corresponding results are obtained for Mueller-Jones matrices (the 4 × 4 real-valued matrices which are the four-dimensional representations of the two-dimensional 2 × 2 complex-valued Jones matrices). We also study the problem for general Mueller matrices; however because of their phenomenological character they do not admit of such criteria as do the Jones and Mueller-Jones matrices. This is because g now depends upon the matrix elements of the Mueller matrix and...
TL;DR: In this article, the use of lowvoltage, low power, and bistable devices to perform a variety of functions including polarization and intensity-based logic gates, input/output displays, optical crossbars, and spatial filtering masks is described.
Abstract: High-contrast, submicrosecond switching ferroelectric liquid crystal spatial light modulators have many applications to optical computing and image processing. In this paper we describe the use of these low-voltage, low-power, and bistable devices to perform a variety of functions including polarization- and intensity-based logic gates, input/output displays, optical crossbars, and spatial filtering masks.
TL;DR: In this article, the intensity and polarization of light scattered by clover in vivo and soil were measured at a number of different angles of incidence and reflectance, and it was shown that the light transmitted through the leaves was negatively polarized.
TL;DR: In this article, an ultrafast time-domain optical multi/demultiplexer utilizing the optical Kerr effect in two birefringent fibres concatenated with each fast axis crossed is proposed.
Abstract: An ultrafast time-domain optical multi/demultiplexer utilising the optical Kerr effect in two birefringent fibres concatenated with each fast axis crossed is proposed. Stable demultiplexing of an ultrashort 30 ps optical pulse train at 1.97 GHz from a gain-switched DFB LD has been successfully demonstrated using CW mode-locked Nd:YAG laser control pulses.
TL;DR: In this article, a carte de la polarisation lineaire optique de la galaxie spirale MS1 is presented, en montrant que le champ magnetique dans le plan de la Galaxie a la forme d'une spirale ouverte.
Abstract: On presente une carte de la polarisation lineaire optique de la galaxie spirale MS1. Les donnees peuvent etre interpretees, en montrant que le champ magnetique dans le plan de la galaxie a la forme d'une spirale ouverte. On discute des implications de ces resultats
TL;DR: In this paper, the synthesis of side-chain liquid crystalline polysiloxanes containing chiral mesogenic side-groups is presented, which are biphasic systems resembling the behavior of phase separated graft copolymers, i.e., they exhibit a micro-phase separated morphology containing main-chain and sidechain domains.
Abstract: : The synthesis of side-chain liquid crystalline polysiloxanes containing chiral mesogenic side-groups, is presented. Differential scanning calorimetry and optical polarization microscopy revealed chiral smectic mesomorphism for all polymers. The last two polymers present also a chiral smectic-C mesophase. All copolymers exhibit two glass transition temperatures; one due to the independent motion of the main chain, the other due to the cooperative but independent motion of the side-groups. Therefore, these liquid crystalline copolymers are biphasic systems resembling the behavior of phase separated graft copolymers, i.e., they exhibit a micro-phase separated morphology containing main-chain and side-chain domains.
TL;DR: It is suggested that cross-polarization measurement using a null detector can serve as a new method for accurate determination of the center of Gaussian laser beams.
Abstract: Polarization properties of Gaussian laser beams are analyzed in a manner consistent with the Maxwell equations, and expressions are developed for all components of the electric and magnetic field vectors in the beam. It is shown that the transverse nature of the free electromagnetic field demands a nonzero transverse cross-polarization component in addition to the well-known component of the field vectors along the beam axis. The strength of these components in relation to the strength of the principal polarization component is established. It is further shown that the integrated strengths of these components over a transverse plane are invariants of the propagation process. It is suggested that cross-polarization measurement using a null detector can serve as a new method for accurate determination of the center of Gaussian laser beams.
TL;DR: In this article, experimental results for a 560 Mbit/s optical heterodyne system using polarisation shift keying were presented, and it was demonstrated that this modulation technique provides up to 3dB gain compared to ASK modulation.
Abstract: Experimental results for a 560 Mbit/s optical heterodyne system using polarisation shift keying are presented. It is demonstrated that this modulation technique provides up to 3dB gain compared to ASK modulation.
TL;DR: In this paper, the polarization properties of volume phase gratings induced in photorefractive materials that are both optically active and linearly birefringent, such as Bi12SiO20, Bi12GeO20 and Bi12TiO20 have been studied under the assumption of a nondepleted readout beam.
Abstract: We study the polarization properties of volume phase gratings induced in photorefractive materials that are both optically active and linearly birefringent, such as Bi12SiO20, Bi12GeO20, and Bi12TiO20. Analytic expressions for the diffraction efficiency and for the orientation and the ellipticity of the diffracted light have been derived for the 〈110〉 and 〈001〉 configurations under the assumption of a nondepleted readout beam. The physical parameters that determine the polarization characteristics of the diffracted light are the orientation of the readout vector, the crystal thickness, the optical activity, and the electric-field-induced linear birefringence. Our results are valid for arbitrary values of these parameters. The particular cases of zero optical activity, zero linear birefringence, a thin crystal, or a specific readout-vector orientation can be deduced from the general formulas. The analytic expressions that we have derived permit an optimal choice of different parameters for the image-processing and beam-coupling applications of these materials.
TL;DR: In this article, the authors used multilongitudinal mode lasers to investigate the polarization properties of long lengths of single-mode fiber cable and found that the individual longitudinal modes are >99 percent polarized after propagation through 54.6 km of cabled fiber; however, the different longitudinal modes have different states of polarization at the output.
Abstract: We have used multilongitudinal mode lasers to investigate the polarization properties of long lengths of single-mode fiber cable. We find that the individual longitudinal modes are >99-percent polarized after propagation through 54.6 km of cabled fiber; however, the different longitudinal modes have different states of polarization at the output. This difference is caused by polarization dispersion, and we estimate a propagation delay difference for the two principal states of polarization to be 0.42 ps in the 54.6 km of cabled fiber.
TL;DR: The properties of thin gelatin films sensitized with a dye (methylene blue) when used as a holographic material are discussed, with the result that the exposed part of the dye becomes dichroic when illuminated with linearly polarized light.
Abstract: The properties of thin gelatin films sensitized with a dye (methylene blue) when used as a holographic material are discussed On illumination the excited dye molecule changes its structure giving a colorless molecule The higher rate of bleaching and therefore the higher diffraction efficiency of the developed phase gratings are obtained in an oxygen-free atmosphere Furthermore, the light absorption probability of the dye molecules depends on its position with respect to the electric vector of the light, with the result that the exposed part of the dye becomes dichroic when illuminated with linearly polarized light This result allows the use of this material for polarizing holography
TL;DR: In this article, a supertwisted nematic liquid crystal layer was applied to compensate for the birefringent effect of the layer and the layer was totally canceled by another super twisted nematic layer of opposite helical sense.
Abstract: Compensation of birefringent retardation is applied to a supertwisted nematic liquid crystal layer. The birefringent effect of the layer is totally canceled by another supertwisted nematic layer of opposite helical sense. Numerical computation confirmed complete extinction of light between crossed polarizers. A highly multiplexable black-white liquid crystal display is obtained with the technique.
TL;DR: In this paper, a new optical integrated circuit (optical IC) pigtailed with a polarization-maintaining fiber for the laser Doppler velocimeter was proposed and demonstrated.
Abstract: In this paper, we propose and demonstrate a new optical integrated circuit (optical IC) pigtailed with a polarization-maintaining fiber for the laser Doppler velocimeter. In this optical IC, a waveguide frequency shifter, a TE/TM mode converter, and a mode splitter are integrated in Z -propagation Ti-diffused LiNbO 3 as well as a waveguide interferometer. Since the optical IC is as long as 32 mm, the waveguide patterning has been made with m accuracy by a laser-beam lithographic system recently developed. Using the fabricated optical IC, the velocity of a moving object has been successfully heterodyne-detected with the signal-to-noise ratio of 25 dB.
TL;DR: A simple method has been developed for control and prevention of polarization fade on a single output lead from a remotely located fiber-optic interferometer, and its application for passive, remotely located sensors is discussed.
Abstract: A simple method has been developed for control and prevention of polarization fade on a single output lead from a remotely located fiber-optic interferometer. The method has been demonstrated using a fiber-optic Michelson interferometer. In contrast to a previously suggested method, only a single detector is required. The technique has application for passive, remotely located sensors. Extension to balanced homodyne detection schemes and coherent communications is discussed.
TL;DR: In this paper, the sensitivity of optical amplifiers to signal polarisation is avoided with use of configurations in which two amplifiers are combined, and experiments demonstrate a polarisation-insensitive amplification for both configurations over a spectral range of at least 80 GHz.
Abstract: The sensitivity of optical amplifiers to signal polarisation is avoided with use of configurations in which two amplifiers are combined. We describe experiments with a series and a parallel arrangement of two optical amplifiers. The experiments demonstrate a polarisation-insensitive amplification for both configurations over a spectral range of at least 80 GHz.
TL;DR: A B = 19.5 mag bright, highly polarized object was detected close to the western hot spot in Pictor A during an optical polarization survey of radio hot spots in classical double radio sources as mentioned in this paper.
Abstract: A B = 19.5 mag bright, highly polarized object was detected close to the western hot spot in Pictor A during an optical polarization survey of radio hot spots in classical double radio sources. The unresolved source exhibits a featureless continuum between 400 and 800 nm and is identified as the optical counterpart of the radio hot spot. It is surrounded by optical filaments aligned roughly perpendicular to the source axis. The hot spot is also marginally detected in an Einstein IPC frame. 17 references.
TL;DR: In this paper, the spectral and polarization characteristics of radiation from a relativistic electron travelling along a deformed helix constrained on a surface of an elliptic cylindroid were investigated.
Abstract: Spectral and polarization characteristics of radiation from a relativistic electron travelling along a deformed helix constrained on a surface of an elliptic cylindroid are theoretically investigated. The present theory shows that the radiation has quasi-circular (elliptical) polarization with higher harmonics. It also gives the general expressions for the radiated electric field which contains both helical and plane undulator radiations as special cases.