Polarization Measurement Method Research Articles

Terahertz polarization real-time imaging based on balanced electro-optic detection

A terahertz (THz) polarization real-time imaging system that can effectively reduce experimental time consumption for acquiring a sample's polarization information is achieved. An alternative THz polarization measurement method is proposed. In this method, a <110> zinc-blende crystal is used as the sensor, and the probe polarization is adjusted to detect THz electric fields on the two orthogonal polarization components. The relative sensitivity of the imaging system to the THz polarization angle is estimated to be less than 0.5°. To illustrate the ability of the system, two samples are designed and measured by using the system. From their THz polarization real-time images, each region of these samples can be precisely presented. Experimental results clearly show the special influences of different materials on the THz polarization. This work effectively extends the information content obtained by THz real-time imaging and improves the feasibility of the imaging technique.

A new method of polarization measurement based on the novel polarization interference imaging spectrometer

A new spaceborne remote sensing principle and method of two-dimensional object polarization measurement, which is based on the novel polarization interference imaging spectrometer (NPIIS) using the field of view compensated Savart polariscope, is presented. Without modification of the optical system of the NPIIS, the Stokes vector, the degree of polarization and polarization direction expressions are derived by measuring the intensity of one pixel on the image plane after three rotations of the polarization interferometer. The method and principle is verified by computer simulation, and the results appear to be well consistent with the theoretical analysis. The research extends the measurement function of the interference imaging spectrometer. Compared with the existing imaging spectrometers which can measure the two-dimensional image information and one-dimensional spectral information, another method to acquire the object information by measuring the polarization state is developed.

Pitting Susceptibility and Semiconducting Properties of Passive Films of 18Cr-18Mn-2Mo-0.9N High Nitrogen Austenitic Stainless Steel

The effects of pH value and chloride ions concentration of the solution on pitting susceptibility and semiconducting properties of passive films formed on 18Cr-18Mn-2Mo-0.9N high nitrogen austenitic stainless steel (HNSS) were investigated using potentiodynamic polarization and capacitance measurement methods, respectively. The anodic polarization curves show that HNSS exhibits excellent pitting corrosion resistance in the solution with different pH values and chloride ions concentration, and the pitting corrosion resistance of HNSS decreases a little with decreasing the pH value or increasing the chloride ions concentration of the solution. The passive films formed on HNSS in the solution with pH values ranging from 1 to 9 or chloride ions concentration from 3.5 wt% to 20 wt% NaCl behave as n-type semiconductors. With increasing the pH value or decreasing the chloride ions concentration, the shallow donor and deeper donor densities decrease and the flat bland potential decreases, and the thickness of space charge layer increases. The deeper donor increases and then the second positive slope of straight linear region disappears with decreasing the pH value or increasing the chloride ions concentration of the solution, which can be attributed to the formation of Cr6+ is depressed.

Near-field Fourier transform polarimetry by use of a discrete space-variant subwavelength grating

We present a unique method for real-time polarization measurement by use of a discrete space-variant subwavelength grating. The formation of the grating is done by discrete orientation of the local subwavelength grooves. The complete polarization analysis of the incident beam is determined by spatial Fourier transform of the near-field intensity distribution transmitted through the discrete subwavelength dielectric grating followed by a subwavelength metal polarizer. We discuss a theoretical analysis based on Stokes-Mueller formalism, as well as on Jones calculus, and experimentally demonstrate our approach with polarization measurements of infrared radiation at a wavelength of 10.6 microm.

Real-time analysis of partially polarized light with a space-variant subwavelength dielectric grating

A novel method for real-time polarization measurement is presented. The method is based on a space-variant wave plate that we realized as a computer-generated space-variant subwavelength dielectric grating. The Stokes parameters of the incident beam are determined by Fourier analysis of the space-variant intensity transmitted through the grating and an analyzer. We discuss the design and realization of such wave plates and demonstrate our technique with polarization measurements of both polarized and partially polarized CO(2)-laser radiation at a wavelength of 10.6 mum.

Anion Electroreduction on a Dropping Mercury Electrode in the Presence of Condensed Layers of Organic Substances

Methods of polarization and chronoamperometric measurements are used to investigate the electroreduction of the BrO¯4 anions on DME. For the first time it is established that this process, which requires that a donor of protons should take part in it, proceeds at a finite rate on CAL of 1-adamantanol and thymine. The obtained data testify that the BrO¯4 electroreduction, which obeys a slow-discharge mechanism in the absence of a CL, in the presence of such a layer is characterized by absolutely different regularities, which are intrinsic to electrochemical processes involving a preceding slow chemical stage. The assumption is made that such a stage may be the restructuring of the hydration sphere of BrO¯4 at the CL/solution interface, which leads to the formation of complexes with the participation of water molecules bound with adsorbed molecules of surface-active organic substances through hydrogen bonds.

Space-Variant Polarization-State Manipulation with Computer-Generated Subwavelength Gratings

Novel methods for space-variant polarization-state manipulation using subwavelength metal and dielectric gratings are presented. By locally controlling the period and direction of the grating, we show that any desired polarization can be achieved. The methods presented in this paper are generic to any portion of the spectrum, and we present experimental demonstrations of our theory using CO2 laser radiation at a wavelength of 10.6 m. Moreover, we exploited our computer-generated subwavelength gratings to demonstrate a polarization Talbot self-imaging, as well as nondiffracting periodically space-variant polarization beams, and a unique method for real-time polarization measurement. We also present novel optical phase elements based on the space-domain Pancharatnam-Berry phase. Unlike diffractive and refractive elements, the phase is not introduced through optical path differences, but results from the geometrical phase that accompanies space-variant polarization manipulation. We intoduce and experimentally demonstrate PancharatnamBerry phase optical elements (PBOEs) based on computer-generated subwavelength gratings such as polarization beamsplitters, optical switches and spiral phase.

Spatial Fourier-transform polarimetry using space-variant subwavelength metal-stripe polarizers

A novel method for rapid polarization measurement is suggested. The method is based on a periodic space-variant polarizer that can be realized by use of subwavelength metal-stripe gratings. The Stokes parameters of the incident beam are determined by Fourier analysis of the space-variant intensity transmitted through the grating, thus permitting real-time polarization measurement. We discuss the design and realization of such polarizers and demonstrate our technique with polarization measurements of CO(2)-laser radiation at a wavelength of 10.6mum.

Improved crystal method for photon beam linear polarization measurement at high energies

A method for photon linear polarization determination based on the measurement of the asymmetry of pairs produced by polarized photons in single crystals within the optimal intervals of pair particle energies is proposed. In difference to the well-known methods the asymmetry in this case is essentially larger. The optimal orientation of crystal is found, which provides the maximal values for analyzing power and figure of merit as well as minimal measurement time.

A new method of accurate polarization measurement on isobaric analog resonance to detect parity non-conservation effect

For the study of parity mixing in the compound states, a method to measure the longitudinal analyzing power Az of the isobaric analog resonance (IAR) as a function of energy in the proton elastic scattering is discussed. A thick target is used and energy loss of the protons in the target is utilized to measure the energy dependence. The energy resolution is presented and the sources of the systematic errors in Az are discussed together with the way of their elimination. The method has been shown to be quite efficient for deriving both the transverse and the longitudinal analyzing powers. The measurement of Az for the s-wave IAR at Ecm=5.86MeV in 90Zr(p,p) and the analysis to derive PNC matrix elements are described.

Antenna polarization measurements using reflection arrangement

Abstract Based on reflection arrangement, two antenna polarization measurement techniques, the absolute polarization measurement method and the polarization‐transfer measurement method are presented with experimental results. In the absolute polarization measurement method or the system calibration, the polarization characteristics of transmitting and receiving dual‐polarization antennas used in the measurement system are determined using the two polarization‐isolated scattering calibrators. In the polarization‐transfer measurement method, the antenna being tested operates in either transmitting mode or receiving mode. Since the transmitting and receiving antennas are located side by side in the measurement system, the phase reference signal between two antennas can be implemented with a short cable.

Method of nuclear polarization measurement in a low-energy polarized target by means of the internal field

The experimental technique of a new type of polarization measurement especially for use with low-energy polarized targets is described. It is possible to derive the nuclear polarization as well as the nuclear spin-lattice relaxation time from measurements of the internal field.

A new method of fluorescence polarization measurement

Summary Two apparatus for measuring polarization fluorescence are described; they are built according to the principle that all the information needed to calculate p can be obtained with a rotating polarizer on the exciting beam in terms of successive maxima and minima of fluorescence intensity emitted at right angles to the direction of excitation. The essential advantages of this method are its simplicity and consequently its easy adaptation on simple fluorimeters, its sensitivity, its aptitude to perform kinetic measurements and the possibility to give an automatized measure of p.

The two-helix method for polarization measurement of meteoric radio echoes

A method employing two helical-beam antennas is described for measuring polarization effect of radio echoes from non-shower meteors of unknown trail orientation. Results obtained by the method are in good agreement with theoretical values and with measurements made on shower meteors by another method by Clegg and Closs.