Showing papers on "Polarization rotator published in 1978"

Polarization effects in short length, single mode fibers

Abstract: The ability to maintain linearly polarized output in single mode fibers is essential for utilization of polarization dependent receiver circuitry Our measurements with long lengths of fiber (200 m) indicate that we can find input polarization angles which yield essentially linearly polarized output However, we found that these polarization effects are greatly influenced by the presence of physical stress on the fiber such as stress due to bending, twisting, mounting, and other variations in ambient conditions We conducted several experiments on short length fibers where special precautions were adopted to assure repeatability of the measurements Our results indicate the existence of a general theoretical model that predicts the output polarization characteristics as a function of input polarization and fiber length The model assumes the presence of two asynchronous, orthogonal modes, uniformly coupled over the entire fiber length The model, however, cannot distinguish between uniformly coupled and uncoupled mode cases based on the output radiation measurements

The polarization of second harmonic plasma emission

Abstract: It is shown that second-harmonic plasma emission is partially polarized in the sense of the ordinary mode of magnetoionic theory only when the Langmuir waves are confined to a small range of angles (less than 30 deg) to the magnetic-field lines. Consequently, Suzuki and Sheridan's (1977) observations of the polarization of harmonic Type III emission implies that (at least in the cases reported) the Langmuir waves must be nearly one-dimensional. For a nearly one-dimensional distribution, the degree of polarization and the frequency of observation should be related to the magnetic field. For the observed polarization of Type III bursts, the implied magnetic-field strengths are strong enough for induced scattering to cause the Langmuir waves to become nearly one-dimensional, which is consistent with the observed sense of polarization. In other applications of harmonic plasma emission where the Langmuir waves might be isotropic or in a loss-cone distribution, polarization in the sense of the extraordinary mode is predicted.

The effect of vacuum birefringence in a magnetic field on the polarization and beaming of x-ray pulsars

Abstract: For current models of x-ray pulsars, vacuum polarization by the magnetic field should not induce any appreciable depolarization of the x rays. Vacuum birefringence could alter the character of the polarization as well as the x-ray beam pattern. The amount of this effect depends on the magnetic-field and density distributions in and near the emission region.

Consequences of light reflection at the interface between two transparent media such that the angle of refraction is 45

Abstract: The reflection of light at the interface between two transparent, homogeneous and optically isotropic media such that the angle of refraction is 45° has the following interesting consequences: (i) the interface relfectivity for the parallel (p) polarization is the square of that for the perpendicular (s) polarization; (ii) the angular deviation of the propagation direction upon refraction is equal to the polarization (or ellipsometric) angle ψ and (iii) the complex reflection coefficient for the p polarization is stationary, in both magnitude and phase, with respect to small charges of the (refractive and/or absorptive) optical properties of either one or both media. Furthermore, it follows from (iii) that: (iv) reflectivity of the p polarization, considered as a function of the ratio of refractive indices of the two media, is at a maximum; and (v) changes of the absolute magnitude and absolute phase of the reflection coefficient for the s polarization, caused by small perturbations of the optical properties, can be measured directly by ellipsometry.

Optical properties of lead monohydrogen phosphate single crystals, PbHPO4

Abstract: The birefringence and the angle φ between the principal axes of the index ellipsoid and the monoclinic axis a (both measured when viewing perpendicular to the mirror plane) have been measured at 25−50°C, i.e. in the vicinity of the 2/m ← m structure phase transition. This data was used to determine the spontaneous birefringence in the ferroic phase. The magnitude of the effective quadratic and linear electrooptic coefficients (that correspond to the transverse electrooptical effect when applying an electric field so that the resulting induced polarization is parallel to the direction of spontaneous polarization, Pi∥Ps) was estimated using our data on P s (T).

Fluorescence polarization detector for the computation of the degree of polarization P

Abstract: A device has been designed and constructed which when used with a commercial fluorimeter allows the computation of the degree of polarization P on a time shared basis.

Magneto-Optical Properties of Ultrasonic Light Diffraction in Glasses

Abstract: The polarization properties of ultrasonic light diffraction in glasses (FR5) under a magnetic field are studied both experimentally and theoretically. When the incident light is linearly polarized, the polarization azimuth of the Diffracted light is measured as a function of the magnetic field and the polarization azimuth of incidence. In the case of a transverse acoustic wave, the polarization azimuth of diffraction is independent of the magnetic field. In the case of a longitudinal acoustic wave, the polarization azimuth of diffraction rotates with increasing magnetic field, but the rotation angle differs from the Faraday rotation and depends on the polarization azimuth of incidence. Theoretical expressions for the polarization states of the diffracted light are derived from Maxwell's equations for a gyrotropic dielectric tensor. Good agreement is obtained between the experimental and theoretical results.

Polarization of Mo Kα ‐radiation of the bragg diffraction in real silicon crystals

Abstract: The results are given for the experimental investigation of the polarization ratio (ϱ∥/ϱ⊥) and the integrated intensity (ϱ⊥) for the Bragg reflections 111, 333, 444 of silicon crystals with different dislocations density (Nd). The measured polarization ratio as a function of Nd and ϱ⊥ is found to have a maximum which is greater than that for the perfect crystal. Attention is drawn to the fact that the polarization ratio maximum for the reflection 111 exceeds unity. The obtained results are analyzed in terms of the mosaic model taking into account the primary extinction for a finite mosaic block and the secondary one between the blocks. The approximation of the mosaic model does not appear to account for the observed polarization ratio maximum. Russian Text Ignored.

Method and apparatus for measuring magnetooptic anisotropy

Abstract: In measuring a change in the polarization state of light attributed to magnetooptic anisotropy, a means for generating optic anisotropy is added to a light source or onto an optical path extending from the light source to a polarization analyzer. This allows high precision analysis of the polarization state of light emergent from the polarization analyzer.

J -dependence of intensity-dependent polarization change

Abstract: J-dependence of intensity-dependent polarization change of the elliptically polarized light in atomic resonance lines is studied both theoretically and experimentally.

Influence of polarization of vacuum in a magnetic field on the propagation of radiation in a plasma

Abstract: It is shown that the polarization of vacuum by a strong magnetic field leads to a substantial change in the polarization, in the angular distribution, and in the emission spectrum of a magnetoactive plasma.

Influence of internal fields on the polarization reversal process in single crystals of ferroelectric-semiconductor SbSI

Abstract: The polarization reversal in SbSI single crystals under the action of bipolar triangular and rectangular pulses has been investigated in the low frequency range (10-3 to 10-1 Hz). It is established that while reversing polarization by retangular bipolar pulses the polarization processes are observed along with the processes of polydomainization in the whole range of frequencies investigated. By the method of dynamic pyroeffect it is shown that polydomainization occurs in samples with a structure of encountering domains. In the course of polarization reversal under the action of bipolar triangular pulses there exists a frequency below which the polydomainization is not observed. For different samples these frequencies fall inside the range of 10-2-10-3 Hz. Experimental evidence obtained enables a possible mechanism of the polydomainization effect to be developed.

Effect of interference of atomic states on the polarization characteristics of multifrequency gas laser emission

Abstract: The effect of interference of atomic states on the polarization characteristics of a multifrequency gas laser is considered theoretically and experimentally. It is shown that minima appear in the relation between the degree of polarization of the emission and the longitudinal magnetic field applied to the active medium, for field strengths at which coherent superposition of atomic states occurs.