Optimization of Hexagonal Boron-Doped Silicate Photonic Crystal Fiber To Obtain Near Zero Flattened Dispersion For Nonlinear Waves By Finite Difference Method

The B2O3-doped silicate photonic crystal fiber (PCF) containing small core and dielectric rods made of lead silicate SF57 has been most intensively investigated for different pump signals centered at 0.65 mm, communication band. This type of doping has been carried out to significantly diminish the upgraded refractive index of silica which enhances special capabilities that lead to an outstanding potential to PCF for the profoundly intense field in the optical Kerr effect. In this paper, the mode analysis has been done by solving a nonlinear wave equation for a Gaussian input beam using the finite difference method under analytical boundary conditions. Numerical results reveal that very minute doping of B2O3 is enough in giving prolonged confinement of beam with flattened dispersion due to ultra-low change in nonlinear behaviour.

Sintered transparent polycrystalline ceramics: the next generation of fillers for clarity enhancement in corundum

A significant proportion of mined natural corundum (ruby and sapphire) contain fractures, which negatively affects a gemstone’s clarity and value. Over the past decades, heat treatment techniques have been developed for either fracture healing, or filling to make such gems marketable. The clarity enhancement processes are mainly based on techniques which are either not durable, as in the case of lead silicate fillers, or do not yield perfect transmittance through a fracture, as in the case of borax based fluxes. Therefore, the gemstone treatment community is actively in pursuit of better techniques for clarity enhancement in corundum. Given that application of pressure is a recent advancement in the heat treatment processes of natural sapphire, it is essential to explore the possibilities regarding different outcomes such treatments can have. In this perspective paper, we have briefly described how application of pressure during heat treatments can lead to in-situ sintering of transparent polycrystalline ceramics within the fractures of corundum, which can result in clarity enhancement. Spinel-structure based fillers can be tailored to mimic corundum in terms of tribological, chemical and optical properties. Therefore, gemstones treated with such fillers will be durable, unlike currently used glass-based filler material. We also provide a possible explanation for ghost-fissures in sapphires heated under pressure, as being a by-product of in-situ sintering process of ceramic fillers that are thermodynamically compatible with Al2O3. The prospect of transparent polycrystalline ceramics in the gem and jewelry industry opens a new field of research in this area, given that ceramic fillers can outperform currently used methods and material for clarity enhancement in gemstones. In essence, we present a novel application for sintered transparent polycrystalline ceramics.

Ultra-High Nonlinear Lead Silicate Photonic Crystal Fiber with Two Zero Dispersion for Supercontinuum Generation Applications

This paper presents a unique type of Lead silicate (SF57) photonic crystal fiber (PCF) with eleven rings of air holes. The PCF promises to yield very large nonlinearity ~13169 W −1 km −1 at 0.75 𝜇𝑚, ~8607 W^(-1) km^(-1) at 1.064 μm and ~4640 W^(-1) km^(-1) at 1.55 μm. The PCF has two zero dispersion at wavelength 0.3 μm and 1.50 μm . The value of nonlinearities is highest reported till now. The PCF contains very low optical mode field, causes large nonlinearity which makes it best suitable PCF for generating supercontinuum.

Synthesis of Pb3O4-SiO2-ZnO-WO3 glasses and their fundamental properties for gamma shielding applications

In this research, we prepared zinc lead silicate glass system with the composition 35Pb3O4-60SiO2- (5-x) ZnO-xWO3 (0 ≤ x ≤ 5 mol %) via the melt-quench method. XRD is explored the nature of the glass system. Ultrasonic velocity, and elastic modulus were experimentally investigated and then the results were confirmed by using the theoretical calculations. It was found that because of molar volume reduction inter-ionic distance\({R}_{i}\), polaron radius \({r}_{p}\), and inter-nuclear distance, \({r}_{i}\)of the investigated glasses are reduced with WO3 content. The basic attenuation factors; mass and linear coefficients denoted by µ/ρ and µ, respectively, were determined employing several simulations for each energy via FLUKA code. As WO3 content increased from 0 to 5 mol %, the µ increased from 0.728 cm− 1 to 0.856 cm− 1 achieving high shielding performance for the sample with x = 5 mol %. At 0.6 MeV with x = 5 mol %, we found that the dose rate of the prepared glass system decreases from 2.35 × 107 R/h at 1 mm to 4.71 × 106 R/h at 4 mm. The values of MFP and HVL are lower than those of the conventional photon shields indicating that our prepared glass samples (especially G5 glass sample) have promising shielding properties to use for x/gamma rays applications.

Influence of Synthesis-Related Microstructural Features on the Electrocaloric Effect for 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 Ceramics

Despite having a very similar electrocaloric (EC) coefficient, i.e., the EC temperature change divided by the applied electric field, the 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 (PMN-10PT) ceramic prepared by mechanochemical synthesis exhibits a much higher EC temperature change than the columbite-derived version, i.e., 2.37 °C at 107 °C and 115 kV/cm. The difference is due to the almost two-times-higher breakdown field of the former material, 115 kV/cm, as opposed to 57 kV/cm in the latter. While both ceramic materials have similarly high relative densities and grain sizes (>96%, ≈5 μm) and an almost correct perovskite stoichiometry, the mechanochemical synthesis contributes to a lower level of compositional deviation. The peak permittivity and saturated polarization are slightly higher and the domain structure is finer in the mechanochemically derived ceramic. The secondary phases that result from each synthesis are identified and related to different interactions of the individual materials with the electric field: an intergranular lead-silicate-based phase in the columbite-derived PMN-10PT and MgO inclusions in the mechanochemically derived ceramic.