Device for converting linear displacements into electric pulses

Translated from Izmeritel'naya Tekhnika, No. 4, p. 14, April, 1993.     

Optical thin-film linear polarization selector fabricated by oblique angle deposition

A linear polarization selector was made from a three-section sculptured thin film deposited using an oblique angle deposition technique. In this device, the circular Bragg reflector with a left-handed helical structure was sandwiched in between two quarter-wave plates with opposite in-plane birefringence. Within the Bragg regime, the normal incident S-polarized light on this device was reflected, whereas the incident P-polarized light was transmitted through it. The microstructure of the linear polarization selector was also examined by scanning electron microscopy.     

Optical polarization imaging

The temporal profiles of the parallel and perpendicular polarization components of a light pulse backscattered from a scattering medium are different. The depth of penetration into the tissue and depolarization of the backscattered light depend on the scattering and absorption characteristics of the tissue. Based on these facts, a novel technique is demonstrated for noninvasive surface and beneath-the-surface imaging of biological systems.     

Enhanced linear polarization for tagged photon beams

The Illinois photon tagging facility has been modified to provide beams with a high degree of linear polarization. The method allows the polarization of an off-axis tagged photon beam to be greatly enhanced by means of a kinematic selection of the post-bremsstrahlung residual electrons that are used for tagging. As an initial test of the system, photon scattering was observed from the strong 1⁺ levels in magnesium and silicon.     

Experimental investigation of linear polarization in high-birefringence single-mode fibers

We report on measurements of linear polarization ratio in high-birefringence fibers as a function of wavelength. Comparison with standard step-index and with dispersion-shifted fibers reconfirms that the modes of polarization-maintaining fibers are not linearly polarized.     

Highly emissive nano rod-in-rod heterostructures with strong linear polarization

We report the synthesis of CdSe/CdS rod in rod core/shell heterostructures. These rods, synthesized using a seeded-growth approach, show narrow distributions of rod diameters and lengths and exhibit high emission quantum efficiencies and highly polarized emission. The degree of polarization is controlled by the inner core rod dimensions, and it is equal or up to 1.5 times higher than the polarization of equivalent sphere in rod systems. Using the method of photoselection we measure the polarization anisotropy at different excitation wavelengths and study the interplay between electronic contribution and dielectric effects in determining the absorption and emission polarization.     

Backscatter linear and circular polarization analysis of roughened aluminum

A study of cross-polarized and copolarized intensities backscattered from roughened aluminum surfaces is presented for both linear and circular incident polarization states. The angular variation of measured Mueller matrices is shown to contain only diagonal elements, as predicted by the reciprocity theorem. The ratio of cross-depolarized to copolarized scattered intensities is significantly larger for circular than for linear input polarization states. In the linear case the ratio saturates beyond 50 degrees , whereas in the circular case the ratio continues to increase monotonically with angle. A phenomenological model for copolarization and cross-polarization intensities is shown to predict the observed behavior of both linear and circular input polarization states up to incident angles of 70 degrees .     

Production of linear polarization by segmentation of helical undulator

A simple scheme to obtain linearly polarized radiation (LPR) with a segmented undulator is proposed. The undulator is composed of several segments each of which forms a helical undulator and has helicity opposite to those of adjacent segments. Due to coherent sum of radiation, the circularly polarized component is canceled out resulting in production of LPR without any higher harmonics. The radiation from the proposed device is investigated analytically, which shows that a high degree of linear polarization is obtained in spite of a finite beam emittance and angular acceptance of optics, if a sufficiently large number of segments and an adequate photon energy are chosen. Results of calculation to investigate practical performances of the proposed device are presented.     

Optical component interface scatter characterization by selective polarization extinction

A procedure for the selective extinction of the scattered light based on "null ellipsometry" [R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, 1977)] is presented. The technique allows scattering measurement from individual layers of a multilayer component by extinguishing the scattered light from the other layer interfaces. The technique is easily applicable to multilayer components with nearly identical surface profiles at every interface and little significant bulk scattering. Analysis is provided to determine the conditions required to extinguish the light from the excluded interfaces isolating the scattered light from the desired interface. An analysis of sensitivity of the extinction conditions to experimental parameters and to layer optical thickness is also provided. Experimental data collected using the technique are compared with measurements made using a white-light optical surface profilometry.     

On converting a dual graph into a block layout

One of the difficulties associated with the application of graph theory to the facilities layout problem is the conversion of the dual graph into a block layout. This paper presents a procedure to address this problem. The procedure exploits the similarities between the graph-theoretic approach and computerized layout-construction procedures, and also resolves some of their differences. It considers the faces of the dual graph one by one and places them in the block layout adjacent to each other in a manner consistent with the adjacencies specified by the dual graph, The procedure is independent.of the manner the maximal planar weighted graph is developed.     

Optical properties of polarizable linear magneto-micropolar fluid

General optical properties of the polarizable linear Magneto-Micropolar fluids are investigated. The constitutive dielectric tensor is generalized to include the effect of magnetic field and gyration vector. The general expression for the refractive index is obtained. When the optical effect of the magnetic field and gyration are negligible, the fluid shows the same birefringent phenomena as a Stokesian fluid and when the effect of the magnetic field or gyration is dominant, the fluid shows double circular refraction. The coupling effect of the magnetic field and gyration vector is considered and the special cases of slow motion and small conductivity are also discussed.     

Variational principles and finite element analysis for polarization gradient theory

The equations of classical polarization gradient theory are studied using variational methods and finite element analysis. Variational principles are derived and specialized to represent the cubic centro-symmetric crystal structure. An isoparametric nine node axisymmetric finite element is developed and used to demostrate the application of the theory. An analysis of the effects of a point charge in a semi-infinite isotropic halfspace including surface tension effects is computed.     

Orthogonal linear polarization tunable-beat ring laser with a superluminescent diode

An orthogonal linear polarization operated ring laser with a superluminescent diode has been demonstrated to generate a tunable optical beat signal. The ring cavity contains a superluminescent diode as the optical gain medium, Faraday rotators, and a variable phase retarder (Babinet-Soleil compensator). By controlling the retarder, we changed the beat frequency in the range from a few tens of megahertz to 100 MHz.