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In this paper Ridge, S-bend waveguide design and analysis has been performed for C-band using various materials like Silica (SiO 2 ), Silicon Nitride (Si 3 N 4 ), Barium Fluoride (BaF 2 ) and Titanium Dioxide (TiO 2 ). We have performed a comparative study and identified Si 3 N 4 as the most suitable material for silicon photonics platform based on lower insertion and propagation losses. Si 3 N 4 based ridge waveguide reduces insertion loss to 5.68dB and propagation loss to less than 1dB/cm. These designed waveguides will be used in variable optical attenuator. Here in this paper, we also propose a variable optical attenuator based on the configurations of a Si 3 N 4 -BaF 2 and TiO 2 -Si 3 N 4 S-bend waveguides. The thermo-optic characteristics of Si 3 N 4 and BaF 2 materials are fully utilized for making variable optical attenuator (VOA). After performing software simulation, simulation results are verified with theoretical results. We get Optical attenuation of 1 to 50 dB with an applied electrical voltage of 0 to 20 V for length of 100 um device with low insertion loss.

Phase formation in the BaF 2 -CeF 3 system has been studied in the aqueous nitrate media by co-precipitation technique with the use of HF and NH 4 F as fluorinating agents. Formation and properties of fluorite-type Ba 1-x Ce x F 2+x (х = 0.32–0.58) and tysonite-type Ce 1-y Ba y F 3-y (y = 0–0.20) solid solutions are described in the present paper.

Our recent study was focused on the emission from Laser Induced Plasma (LIP) at the delay times of tenths of microseconds after the laser pulse. At these long delays, the spectrum is dominated by the broadband molecular emission and plasma induced luminescence (PIL) produced by a luminescent matrix; only solitary atomic emission lines can be seen. Barium fluoride BaF2 activated by thulium (Tm) is a famous scintillator that presents the promising object for LIP in terms of both the potential for BaF molecular emission and Tm3+ PIL. The detection of molecular and PIL bands presents a new opportunity for analysis of halogens and rare-earth elements, which are the difficult objects for LIBS. In this paper, we show that the UV, Green, Extreme Red, and Infrared molecular bands from BaF and blue luminescence from Tm3+ are present in the LIP emission spectra while the detection of atomic emission from F I and Tm I was impossible with the same experimental setup. Thus, the detection of molecular emission and PIL can be more sensitive than the traditional detection of emission from atoms and ions.

Lead–gallium glasses, due to the absence of typical glass-forming components, are characterized by an increased tendency to crystallization. Despite this, they are interesting materials due to a shift of IR absorption edge up to 6–7 μm. The paper considers how the SiO2 dopant affects thermal stability and the UV–VIS and IR transmittance of lead-gallium glasses. The base lead-gallium glass (0.75PbO·0.25Ga2O3) was modified by the addition of 5, 10 and 15 mol% SiO2, respectively. DTA/DSC data showed that the glasses are characterized by the multi-stage crystallization, which is changed with the amount of silica doped. The XRD analysis confirmed that: (i) different forms of lead oxide crystallize after heat treatment of the glass, and (ii) the Ga2PbO4 phase is formed at higher temperatures. The silica admixture allowed inserting a few percent of BaF2 into the lead–gallium glass structure. It was found that a transparent glass–ceramic based on the lead-gallium glass with a low phonon barium fluoride phase can be obtained during the thermal treatment. The study of UV–VIS–IR transmittance shows that 10–15 mol% SiO2 in the lead-gallium glasses diminishes the absorption band in the range of 2.6–4 μm due to the presence of hydroxyl groups and simultaneously reduces transmittance in the range of 5–6.5 μm from 10 to 20%. Introduction of SiO2 to the glass results in the increase of transmittance in the shorter wavelength region and the UV-edge shift is observed. It was also confirmed that the BaF2 nanocrystallites exert s no effect on the transmittance of the spectrum analyzed.

Coated-conductor applications of YBCO require YBCO layers with high J/sub c/ and a thickness of several micrometers. The barium fluoride process offers a convenient way of depositing crack-free fluorinated precursor layers up to 5 microns thick. However, converting thick precursor layers into c-axis-oriented YBCO films is challenging due to extensive nucleation of random grains. In this paper we address this problem with both a theoretical and experimental analysis of YBCO nucleation. We utilized optical polarization contrast to observe YBCO nuclei imbedded in the precursor matrix. We observed that the nuclei density strongly depends on processing parameters, with the oxygen partial pressure being one of the strongest factors. During ex-situ processing the nuclei merge and form grains and the nuclei density is, therefore, directly related to the grain size of YBCO film. It is desirable to have a small grain structure, since large grains do not connect well and the J/sub c/ of such a film is low. However, attempts to increase the nuclei density also generates more randomly oriented grains. Therefore the optimization of ex-situ processing is essentially finding a balance between c-axis grain density and random grain content.

ISSN 0967–9782 to metallic barium and other barium compounds, including barium oxide, hydroxide, peroxide, and a variety of salts. Barium compounds are used widely in industry and medical science ‘as loaders for paper, soap, rubber and linoleum, as drilling muds in oil rigs, in the manufacture of valves and in the production of lights and green flares .. . as pigments in the manufacture of paints; in cement where concrete is exposed to salt water; in the radio industry to capture the last traces of gases in vacuum tubes; in the ceramic and glass industries; as insecticides and rodenticides; as extinguishers for radium, uranium, and plutonium; and as contrast material in X-ray medical examination’.1 Barium sulphate is the source of most Ba compounds but barium carbonate 3 ) is used both in the ceramic industry and to make barium fluoride. It has sometimes been suggested that for use in pottery glazes, barium sulphate 4 ) should be substituted for 3 due to its lower solubility (Table 1).2 It should be remembered that the ultimate toxic agent is the barium ion, and so the relative toxicity of barium compounds is directly related to their ability to dissolve or form ions. This can cause problems with the burning off of the sulphur dioxide from the glaze during firing resulting in pinholing. In some cases the substitution may be satisfactory, and so the danger to the potter using the barium can be lessened, but it does not help the problem of barium leaching from glazes used on domestic ware and thus the danger to the user.

The scanning soft X-ray microscope operating at Hasylab/Desy has been developed to combine lateral and temporal resolution, tunability and various conventional spectroscopy techniques. Different mirror optics are used to form a microprobe in the energy range 15–1500 eV. A grazing incidence ellipsoidal mirror provides a resolution of 1 μm over the entire energy range, and in the vacuum ultraviolet region below 30 eV, 0.15 μm can be achieved with a Pt-coated Schwarzschild objective. Due to the large working distance of the optics used, the detection and analysis of several surface signals are comparatively simple. Detectors and spectrometers for photoelectrons, luminescence, fluorescence, desorbed ions, reflected, scattered and transmitted light are built in permanently into the microscope. Furthermore, some combinations of the different methods can be used for simultaneous measurements. In this paper the technical developments of recent years are described. A short representation of some exemplary applications will give an insight into the work of our group and illustrate the characteristics of the microscope. The following topics are discussed: cross-luminescence of barium fluoride, visible luminescence and degradation of porous silicon, photoluminescence of ceramics, chemical contrast in photoemission spectroscopy, and Bragg reflection as a contrast mechanism in X-ray microscopy.

The paper is focused on numerical analysis of lasing in blue and yellow spectral range of a Dy:ZBLAN fiber laser system, working in a Fabry-Perot configuration. A mathematical model based on measured spectroscopic data, as well as fiber structural parameters is implemented and yielded results are confronted with available experimental data. A reasonable agreement is found despite relative simplicity of the proposed solution.

The Near InfraRed Camera (NIRCam) for the James Webb Space Telescope (JWST) is a refracting camera system. Its unique performance derives from the Lithium Fluoride, Barium Fluoride and Zinc Selenide lenses that provide aberration and color correction over the large operating wavelength. This paper describes the optical prescription, lens materials and prototype characterization for the camera lenses.

In this paper, new results about a transient femtosecond index grating in barium fluoride has been presented. There is a strong indication that the lifetime of the grating is only limited by the pulse width of the laser. Additionally, it is shown how the transient grating promotes highly efficient third-harmonic generation and diffraction due to a self phase matching mechanism. The immediate build-up and decay opens the way to an application as a femtosecond switching device.

Interference of two non-collinear femtosecond laser pulses induces, due to the optical Kerr effect, a refractive index grating in a thin slide of barium fluoride crystal. Self diffraction and diffraction of the third harmonic of the incident light, generated within the slide, is observed to several orders with an efficiency of better than 10 %. The intensity of the third harmonic is so high that for several diffraction orders the fluorescence of a white paper screen is easily visible to the naked eye. All effects are only present upon coincidence of both incident pulses, showing their instantaneous nature.

The Papanicolaou (Pap) smear is the technique used to screen for abnormalities in cervical cells that may be related to cervical cancer and other problems. A number of research groups have reported results that indicate the infrared or NIR spectroscopy can be used to differentiate between samples of normal cervical cells and abnormal cells.In this paper we will describe studies performed on cervical cell samples with an infrared microscope and a motorized x-y stage. This configuration allowed us to “Map” the sample in 100 micron increments, where an infrared spectrum is acquired at each point. This integrated system also allowed chemometric algorithms developed with the Nicolet TQ Analyst software to be automatically applied to the spectral data. Samples of cervical cells were obtained from patients using the standard procedure. Part of the sample was used to prepare the Pap smear slide and the remainder was placed in a saline solution and centrifuged for several minutes. The cell suspension was then applied to a Barium Fluoride 5mm X 5mm window and dried.

Fluoride films (made from barium, calcium, strontium, and lead fluorides) tend to crystallize when they are sputtered. For an optical thickness more than 3-5 µm, their transparency in the visible region decreases because of losses to scattering. This paper discusses the optical characteristics of doped films of barium, calcium, strontium, and lead fluorides and shows that it is possible to obtain films that are simultaneously transparent in the visible and IR regions. Doped barium fluoride films were used as a basis for synthesizing, fabricating, and studying interference coatings that operate in the mid-IR and the visible regions. We give as an example coatings simultaneously used in laser systems with wavelengths of 10.6 and 0.63 µm. © 2004 Optical Society of America

Alkalihalogenide (LiF, NaF, NaCl, NaBr, KCl, KBr, KJ) wurden im Hochvakuum auf (111)-Flachen von Calcium- und Bariumfluorid aufgedampft. Vor dem Bedampfen wurden die Tragerkristalle an der Luft gespalten. Die orientierte Kristallisation der isotypen Alkalihalogenide auf den beiden isotypen Substraten wird auf Grund zahlreicher elektronenmikroskopischer Aufnahmen beschrieben und diskutiert. Auser der (111)-Orientierung treten noch (100)-Orientierungen und bei den Fluoriden die (110)-Orientierung auf. Als Grundtendenz wird bei den Verwachsungsgesetzen der Einflus ubereinstimmender Symmetrie der simultanen Netzebenen deutlich. Bei Variation von Tragertemperatur und Ubersattigung kommt die Wirkung von Oberflachenstufen und Adsorptionsschichten auf die Epitaxie zum Ausdruck. Die Keimdichte zeigt einen Zusammenhang mit der Gitterenergie der Depositkristalle. Es wird der Versuch unternommen, einige Fragen vom Standpunkt der kinetischen Theorie der Epitaxie zu deuten. Alkali halides (LiF, NaF, NaCl, NaBr, KCl, KBr, KJ) have been deposited on (111)-faces of calcium- and barium fluoride in a high vacuum. Before deposition the substrate crystals have been cleaved in air. In this paper the oriented crystallization of the isotype alkali halides on the isotype substrates, studied by means of numerous electron micrographs, is described and discussed. Besides the (111)-orientation (100)-orientations occur and at the fluorides the (110)-orientation too. Principally the orientation relations are determined by the corresponding symmetry of the simultanous faces. The effect of surface steps and adsorption layers on epitaxy is observed in varying substrate temperature and supersaturation. Relations exist between the density of nuclei and the lattice energy of the deposite crystals. An attempt is made to interpret certain problems from the viewpoint of the kinetic theory of epitaxy.

The objective of this paper is to discuss the interaction of other fields with halide glasses and the impact of these interactions. The fields to be discussed are several fields of chemistry, sol-gel science and polymer fiber optics.