Analysis of Faraday effect in multimode tellurite glass optical fiber for magneto-optical sensing and monitoring applications

The design and fabrication of a tellurite glass multimode optical fiber for magneto-optical applications are presented and discussed. The analysis of the polarization shows that an optical beam, linearly polarized at the fiber input, changes to elliptically polarized with an ellipticity of 1∶4.5 after propagating down the fiber. However, the elliptical distribution remains unchanged with or without an applied magnetic field, demonstrating that no circular dichroism occurs within the fiber. The Verdet constant of the tellurite glass in the fiber is measured to be 28±0.5 rad·(T·m)-1, diverging by less than 3% from the Verdet constant found on the same glass composition in bulk form. These results demonstrate the feasibility to develop reliable tellurite glass fibers by the preform drawing method for magneto-optical applications.     

Single glass block Faraday effect current sensor with homogeneous isotropic closed optical circuit

A new scheme is proposed for achieving a closed, homogeneous, and isotropic optical circuit necessary for high-accuracy optical-current sensors. It makes use of a single solid polygonal solid with reflection surfaces coated by quarter-wavelength dielectric thin-film layers for the Faraday cell. We derive the design principle and show numerically its applicability in various Faraday materials. The cross talk with the surrounding current is investigated in particular detail both theoretically and experimentally. In the example experiment with a SF57 Faraday material, a low cross talk is demonstrated for nearby currents.     

Temperature dependence of helium permittivity through freely poured quartz glass powder

The temperature dependence of relative helium flow through a free poured powder of amorphous SiO₂ held in a quartz glass cell is determined experimentally.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 2, pp. 249–253, August, 1987.     

Complex Faraday rotation in microstructured magneto-optical fiber waveguides

Magneto-optical glasses are of considerable current interest, primarily for applications in fiber circuitry, optical isolation, all-optical diodes, optical switching and modulation. While the benchmark materials are still crystalline, glasses offer a variety of unique advantages, such as very high rare-earth and heavy-metal solubility and, in principle, the possibility of being produced in fiber form. In comparison to conventional fiber-drawing processes, pressure-assisted melt-filling of microcapillaries or photonic crystal fibers with magneto-optical glasses offers an alternative route to creating complex waveguide architectures from unusual combinations of glasses. For instance, strongly diamagnetic tellurite or chalcogenide glasses with high refractive index can be combined with silica in an all-solid, microstructured waveguide. This promises the implementation of as-yet-unsuitable but strongly active glass candidates as fiber waveguides, for example in photonic crystal fibers.     

Temperature dependence of luminescence behavior in Er/Yb co-doped transparent phosphate glass ceramics

The effect of temperature on the luminescence intensity of up-conversion and near infrared in Er³⁺/Yb³⁺ co-doped phosphate glass ceramics has been investigated. Efficient green and red up-conversion luminescence and strong infrared fluorescence at 1.54 μm wavelength are observed under excitation of 975 nm. The fluorescence intensity is changing at different temperature and the results are explained with the level transitions in Er³⁺/Yb³⁺ co-doped system. Meanwhile, the lifetime of Er³⁺:⁴I_13/2 level corresponding to different operating temperature and pump power is also discussed, and the experimental results are fitted using multiphonon relaxation theory.     

Hybridization effect on the mechanical properties of curaua/glass fiber composites

The aim of this paper was to evaluate the effect of hybridizing glass and curaua fibers on the mechanical properties of their composites. These composites were produced by hot compression molding, with distinct overall fiber volume fraction, being either pure curaua fiber, pure glass fiber or hybrid. The mechanical characterization was performed by tensile, flexural, short beam, Iosipescu and also nondestructive testing. From the obtained results, it was observed that the tensile strength and modulus increased with glass fiber incorporation and for higher overall fiber volume fraction (%V_f). The short beam strength increased up to %V_f of 30 vol.%, evidencing a maximum in terms of overall fiber/matrix interface and composite quality. Hybridization has been successfully applied to vegetable/synthetic fiber reinforced polyester composites in a way that the various properties responded satisfactorily to the incorporation of a third component.     

Temperature dependence of electronic relaxation time in the Sondheimer size effect of copper

Measurements of the phonon-limited relaxation time _T are made in copper by means of the Sondheimer size effect. It is found that the relaxation rate 1/ _T varies approximately as T ⁵ when the magnetic field is directed in the [110] direction, while it varies approximately as T ⁵ below 8 K and as T ^3.3 above 8.5 K when the magnetic field is directed in the [100] direction. The results are discussed in terms of diffusive and catastrophic scattering.This work was supported by Grant-in-Aid for Scientific Research from the Ministry of Education of Japan.     

Phase diagram of the As-S system

Thermodynamic modeling of phase equilibria is used to consistent p-T-x phase diagram of the As-S system. Experimental evidence is presented that As₂S₅ is a metastable phase at moderate pressures. Analytical expressions are derived for the subsolidus phase equilibria in the As-S system. It is shown for the first time that crystalline As₄S₃ sublimes congruently and that two liquid-vapor azeotropes exist in the As-S system.     

玄武岩纤维和玻璃纤维的耐碱性及其网格布对混凝土双向板弯曲性能的影响

为了研究玄武岩纤维网格布和玻璃纤维网格布的耐碱腐蚀性及其对混凝土方板双向受弯性能的影响,进行了玄武岩纤维和高锆玻璃纤维的耐碱试验和其网格布增强混凝土双向板的弯曲性能试验。借鉴欧洲EFNARC标准,利用四边简支方板试验,对比分析了不同纤维网格布对混凝土方板的双向增强效应。结果表明,与玄武岩纤维相比,高锆玻璃纤维的耐碱腐蚀性更好。纤维网格布较高的双向受拉性能可改善混凝土双向板的内力和应力重分布能力,玄武岩纤维网格布和高锆玻璃纤维网格布使水泥双向板的受弯承载力分别提高了48%和59%,高锆玻璃纤维的双向增强作用优于玄武岩纤维。      

Fiber-linked Faraday effect current sensor by use of a flint glass cell with dielectric-coated retardation-compensated total reflection surfaces

A new type of Faraday effect optical current transformer has been developed that uses a single block of square flint glass with dielectric-coated total reflection surfaces as the sensing element. Numerical calculation has shown that the coating of two dielectric layers of 45.59-nm-thick Ta2O5 and 448.35-nm-thick SiO2 films on a flint glass surface produces zero retardation total reflection for the 45 degrees incident angle of light at lambda = 840 nm with great incident angle, wavelength, and film thickness tolerances. A fiber-linked current transformer has been constructed and experimentally demonstrated to exhibit high isolation from surrounding currents as well as high stability against mechanical disturbances.     

Temperature dependence of the Brillouin linewidth in water

In the frequency spectrum of light that is scattered in liquid water there is a central elastically scattered peak that is due mainly to scattering by suspended particles; and, there is a peak on each side of the central peak that is displaced by the Brillouin frequency shift. The Brillouin shift is a direct measure of sound speed. The linewidth of the Brillouin shifted lines is dependent on the bulk and shear viscosity of water as well as its density, thermal conductivity, and specific heat. The linewidth of the Brillouin peaks has been investigated in laboratory experiments over a range 1°C to 35°C. The frequency spectrum of back-scattered laser light was analysed using a scanning Fabry-Perot etalon. A strong dependence of the linewidth of the Brillouin shifted lines on temperature was found. In particular, for low temperatures in the range 10°C down to 1°C the linewidth shows an increase from 750 MHz to 1.4 GHz.     

Temperature dependence of the effect of liquid metals on the long-time strength of solid metals

This article describes long-time strength tests carried out at various temperatures on copper in liquid bismuth, a nickel alloy in sodium, and armco iron in zinc. It is shown that experimental data is in good agreement with theoretical concepts about the effect of adsorption, corrosion and diffusion of liquid metals on the properties of solids.     

An optical polarization-bistable element based on the Faraday effect

An optical polarization-bistable element scheme based on an He-Ne laser (λ = 3.39 μm) with a Faraday cell in the cavity is considered for the first time. A sample of such cavity having the shape of a parallelepiped has been manufactured from an yttrium iron garnet single crystal and a theoretical analysis of this element in terms of the Jones matrices has been performed. It is established that the polarization bistability can be observed for a single-trip Faraday rotation of 45°. Experiments with the device based on a hybrid bistability scheme showed that, under certain conditions, the circular polarization is reversibly switched between σ⁺ and σ^?.