Μm In Glass Research Articles

A Partial Coherent Interferometry for measuring the thickness of a dynamic liquid sheet

This work presents a non-invasive technique, Partial Coherent Interferometry, for measuring the thickness distribution of a dynamic liquid sheet. It utilizes the linear relationship between the degree of coherence and the optical path difference to determine the thickness of the sheet. In an interferometer using a partial coherent laser, the interference patterns before and after the liquid sheet insertion are digitally recorded. The relative thickness distribution is determined by applying a phase unwrapping process to the recorded interference pattern. By measuring the change of the degree of coherence introduced by the sheet, the absolute thicknesses at the reference points are determined. By matching the relative thickness to the absolute thicknesses at different points, the absolute thickness distribution is retrieved. To verify the reliability of this method, a glass sample and a static ethanol film, both with nominal thicknesses (152.4 µm), are measured first. The results, a nearly uniform thickness of 148.8 ± 1.8 µm for glass and a varying thickness distribution around 154.6 µm for static ethanol film, show the capability of this method to measure a two-dimensional thickness distribution of a thin liquid sheet. Then a dynamic impinging sheet formed by the two ethanol jets with Reynolds number 763 and Weber number 143 is measured by Partial Coherent Interferometry. The thickness distribution ranges from 26 to 38 µm with an uncertainty of 2.1 µm.

Preparation of Y2Ti2O7 pyrochlore glass-ceramics as potential waste forms for actinides: The effects of processing conditions

Glass-Y2Ti2O7 pyrochlore was fabricated by sintering the mixture of glass precursor powder and (YTi)-composite which was prepared by a soft chemistry route. X-ray diffraction and Raman spectroscopy confirmed that the phase pure pyrochlore was crystallized in-situ in amorphous glass matrix at 1200 °C with dwelling time over 1 h. Pyrochlore was formed in glass matrix with cooling rate ∼0.1–40 °C/min, and independent of addition of alkali/alkaline earth fluorides. Glass matrix was able to accommodate/dissolve small amounts of impurities and the mean pyrochlore particle size was between 1 and 2 μm in glass observed by scanning electron microscopy.

Glass structure and NIR emission of Er3+ at 1.5 μm in oxyfluoride BaF2–Al2O3–B2O3 glasses

The glass structure, photoluminescence properties of Eu3+, Judd–Ofelt analysis, and near infrared emissions of Er3+ at 1.5μm in the oxyfluoride glasses and glass–ceramics of 1Eu2O3- or 1Er2O3-doped 50BaF2–xAl2O3–(50−x)B2O3 (x=0–25mol%) were investigated. It was clarified on the ground of Raman scattering spectroscopy and F1s and O1s XPS measurements that the glass with no Al2O3 (1Er2O3–50BaF2–50B2O3) is composed of BO3, BO2F and BO3F units with F–Ba bonds. The glasses with 25Al2O3 (1Er2O3–50BaF2–25Al2O3–25B2O3) is mainly composed of BO3− and Al(O,F)x units. Existence of non-bridging oxygen was not detected by O1s-XPS spectra. It was proposed that these structures are largely affected on crystallization behavior, e.g., the glass with no Al2O3 forms BaF2 and β-BaB2O4 due to Ba–F bonds and the glass with 25Al2O3 forms BaAlBO3F2 because the glass structure composed of BO3 and Al(O,F) units is similar to the BaAlBO3F2 crystal structure. Judd–Ofelt parameters of Er3+ and Eu3+ in the glasses showed almost the same values in Ω4 and Ω6 for each glass, on the other hand Ω2 decreased with addition of Al2O3. The emission spectra of Er3+ at 1.5μm in the glasses and glass–ceramics with BaAlBO3F2 crystals showed broad peaks. It is proposed that oxyfluoride glasses and glass–ceramics based on the BaF2–Al2O3–B2O3 system have a high potential for optical device applications such as broadband optical amplifiers.

On the mechanism of non-linear optical attenuation at 1.3–1.5 μm in arsenic sulfide and tellurium oxide glasses

The mechanism of optical non-resonant non-linear refraction and absorption/attenuation in glasses at 1.3–1.5 μm is of interest for efficient all-optical switching in optical fibre telecommunications. We discuss the mechanism of non-resonant non-linear attenuation (loss) at 1.3–1.5 μm in glasses with the largest linear refractive indices, such as As 2S 3- and TeO 2-based glasses. These glasses are transparent and possess the largest non-resonant non-linear refraction at 1.3–1.5 μm to date (up to 10 −14 cm 2/ W ), allow single-mode fiberization and therefore are suitable for all-optical fibre switching. We show that with a single beam Z-scan technique we identify the contribution of small-angle non-linear scattering to the total non-linear attenuation at 1.3–1.5 μm. We show that small-angle non-linear scattering does contribute to the non-linear attenuation at such irradiances at which non-linear absorption is not present yet.

Epoxy-based all-solid-state poly(vinyl chloride) matrix membrane calcium ion-selective microelectrodes

Calcium ion-selective microelectrodes have been constructed from PVC matrix membranes containing a calcium bis{di[4-(1,1,3,3-tetramethylbutyl)phenyl]phosphate} electroactive component with dioctyl phenylphosphonate, tripentyl phosphate or trioctyl phosphate as a plasticising solvent mediator, and from the Philips IS 561/SP membrane. The electrode membranes are backed with a silver-based conductive epoxy implanted with a copper wire for electrical contact. Of the three types of electrodes designed, namely, glass capillaries with a pre-formed membrane (type A) or an applied membrane (type B) and infrared heat-drawn Perspex capillaries with applied membrane (type C), the most functional are types B and C, which have functional lifetimes of 6 and 10 d, respectively.The electrodes have tip diameters of 1–3 µm for glass and 5–10 µm for Perspex, the bevelled tip in the latter ensuring a sharp edge.

The effect of passivation thickness on the electromigration lifetime of Al/Cu thin film conductors

Although it has become common practice to cover thin film conductors with tough passivation layers, the reliability of the underlying conductor has not been well established. Most investigators have observed an increase in lifetime for stripes covered with glass as compared to uncovered stripes, but have disagreed as to the extent and the cause of this effect. A research program was undertaken in which the electromigration lifetime of Al/Cu conductors was studied as a function of passivation thickness. Stripes covered with 1.5 μm of glass lasted longer than those which were not covered. A further increase in lifetime was found for samples with thicker glass, but a change in failure mode was also observed. All uncovered stripes and all stripes covered with thin glass failed by open circuit, whereas those with thick glass failed by short circuit, as well. Electromigration-induced compressive stresses are believed to be responsible for these observations.