Emergence of geometrical optical nonlinearities in photonic crystal fiber nanowires

We demonstrate analytically and numerically that a subwavelength-core dielectric photonic nanowire embedded in a properly designed photonic crystal fiber cladding shows evidence of a previously unknown kind of nonlinearity (the magnitude of which is strongly dependent on the waveguide parameters) which acts on solitons so as to considerably reduce their Raman self-frequency shift. An explanation of the phenomenon in terms of indirect pulse negative chirping and broadening is given by using the moment method. Our conclusions are supported by detailed numerical simulations.Comment: 5 pages, 3 figure

Optical performance of neodymium nanoparticles doped tellurite glasses

A series of neodymium NPs doped tellurite glass with composition of (TeO2)0.7(B2O3)0.3]0.7 (ZnO)0.3}1- x (Nd2O3 NPs) x (x = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05 mol%) was fabricated via melt-quenching method. Density and molar volume were measured and analyzed for the glass series. The optical properties of neodymium NPs doped tellurite glass were measured by UV–Vis spectrometer, photoluminescence and Z-scan technique. The optical band gap energy of the glass network was in the range of 3.178–3.209 eV. The upconversion emission of the laser glass excited at 800 nm was found in the ultraviolet region. Electronic polarizability, oxide ion polarizability, optical basicity and metallization criterion were calculated. Moreover, linear absorption coefficient, α, nonlinear refractive index ƞ (cm2/W), nonlinear absorption, β (x 10−3) and third order susceptibilities, χ (x 10−6) were measured. The optical efficiency of neodymium NPs doped tellurite glass exhibited excellent properties for its application in laser glass

Characteristic temperatures and microhardness of (ZnO)x-(AlF3)y-(TeO2)z tellurite glass systems

Glass transition temperature Tg and softening temperature Ts were measured by the differential thermogravimetric analysis DTA in the temperature range 300-850 K of ternary zinc oxyfluoro tellurite (ZOFT) with the composition (ZnO)x-(AlF3)y-(TeO2)z where (5 D, softening temperatures Ts(calc) and microhardness Hvof ternary zinc oxyfluoro tellurite (ZOFT) have been calculated by using ultrasonic velocities data. The compositional dependence of these physical quantities were discussed to understand the rigidity and compactness of the glass system studied

Elastic moduli of TeO2– PbO glass system

Binary glasses (1 − x)(TeO2) − x(PbO) with x = 0, 0.10, 0.15, 0.20, 0.25, 0.30 mol% prepared using the melt quenching have been studied in this work. The amorphous nature of the glasses is confirmed by XRD analyses. Density, ρ and molar volume, Vm were measured for more information on structural changes. The ultrasonic velocities (longitudinal and shear) were obtained using the method of pulse-echo at 5 MHz resonating frequency. The elastic moduli, namely longitudinal (L), shear (G), Young (E) and the bulk (K) moduli were obtained from the density and ultrasonic velocities measurement. The softening temperature (TS), Debye temperature (θD), Poisson’s ratio (σ), fractal bond connectivity (d), microhardness (H) and acoustic impedance (Z) were obtained from the elastic moduli. The transition temperature (TgTg) and thermal expansion coefficient (αP) were also calculated. The experimental elastic moduli data and the values calculated theoretically from the bond compression, Makishima–Mackenzie, and Rocherulle models were compared in this work

Elastic properties of TeO2-B2O3-Ag2O glasses.

A series of glasses [(TeO2) x (B2O3)1−x ]1−y [Ag2O] y with x = 70 and y = 10, 15, 20, 25 and 30 mol% were synthesised by rapid quenching. Longitudinal and shear ultrasonic velocity were measured at room temperature and at 5 MHz frequency. Elastic properties, Poisson's ratio, microhardness, softening temperature and Debye temperature have been calculated from the measured density and ultrasonic velocity at room temperature. The experimental results indicate that the elastic constants depend upon the composition of the glasses and the role of the Ag2O inside the glass network is discussed. Estimated parameters based on Makishima–Mackenzie theory and bond compression model were calculated in order to analyse the experimental elastic moduli. Comparison between the experimental elastic moduli data obtained in the study and the calculated theoretically by the mentioned above models has been discussed

Lead borate glasses and synergistic impact of lanthanum oxide additive: optical and nuclear radiation shielding behaviors

Composition of (50 − x) B2O3–30PbO–20ZnO–xLa2O3 (x = 0, 1.5, 3, 4.5, and 6) wt% glass system were synthesized using quench melt technique and simulated for their nuclear radiation shielding properties. Moreover, UV–visible absorption spectrum among 190–1100 nm and the glass optical parameters were measured. The optical energy gap (Eg), the single-oscillator energy (Eo), the dispersion energy parameter (Ed), refractive index (n), and refractive dispersion index (no) were estimated. The obtained results indicated that (Eg) was decreased with increasing La2O3 content, but the refractive index (n) was increased. The addition of La2O3 to glass network could provide preferable shielding features. The chosen amount of La and another metal oxide has been added to the glass. Shielding parameters such as half-value layer (HVL), mean free path (MFP), mass attenuation coefficient (MAC), and exposure rate in the photon energy range 15–300 keV have been simulated by MicroShield software. These results illustrate that the La5 glass sample has the best radiation shielding properties, among other investigated glasses. This type of glass sample can utilize for the construction of the monitoring screening windows in radiation areas, plats, or screening windows in X-ray diagnostic and for the walls of CT-scanner rooms. © 2020, Springer Science+Business Media, LLC, part of Springer Nature

Novel Tm3+-doped fluorotellurite glasses with enhanced quantum efficiency

In this paper, new highly Tm3+-doped tellurite glasses with host composition 75TeO2-xZnF2-yGeO2-12PbO-3Nb2O5 [x(5-15), y(0-5) mol%] are presented and compared to the Tm-doped tellurite glasses based on the traditional host composition: 75TeO2-20ZnO-5Na2O mol%. Enhanced quantum efficiency from 3F4 level was observed for the proposed glasses and thermal stability and viscosity values make them suitable for optical fiber drawing. Besides the host composition, substantial influence of Tm3+ concentration on luminescence and lifetime of excited 3F4 and 3H4 states were discusse

Synthesis, physical, optical, mechanical, and radiation attenuation properties of TiO2–Na2O–Bi2O3–B2O3 glasses

A series of bismo-borate (50-x)B2O3-xTiO2-15Na2O–30Bi2O3 glass samples (where x = 0, 2.5, 5, 7.5, and 10 wt%) doped with TiO2 were fabricated via the melt-quenching technique. The gamma and neutron shielding, physical, optical, and mechanical properties of the prepared samples were investigated. The experimental results were measured using an HPGe detector. 152Eu, 133Ba, 137Cs, and 60Co radioactive sources were used with energies in the range of 81–1408 keV. The experimental results were compared with both the FLUKA code and the XCOM database. The addition of TiO2 increased the density of the glass samples and decreased their molar volume. The mass attenuation coefficient (MAC) decreased as photon energy decreased, while it increased as TiO2 concentration increased. The half value layer (HVL) and mean free path (MFP) of the glass samples increased when the photon energy increased and decreased as the TiO2 concentration increased. The absorbance of the present samples is enhanced by using TiO2, meaning they can be used to protect humans from UV light. Both direct and indirect band gaps decreased as TiO2 content increased from 0 to 10 wt %. Moreover, the electronic transition between localized states is valid in the present samples. The radiation shielding, optical, physical, and mechanical properties of the fabricated glass samples demonstrate their utility for diagnostic gamma shielding. © 2020 Elsevier Ltd and Techna Group S.r.l

Glassy State Lead Tellurite Nanobelts: Synthesis and Properties

The lead tellurite nanobelts have been first synthesized in the composite molten salts (KNO3/LiNO3) method, which is cost-effective, one-step, easy to control, and performed at low-temperature and in ambient atmosphere. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrum, energy dispersive X-ray spectroscopy and FT-IR spectrum are used to characterize the structure, morphology, and composition of the samples. The results show that the as-synthesized products are amorphous and glassy nanobelts with widths of 200–300 nm and lengths up to tens of microns and the atomic ratio of Pb:Te:O is close to 1:1.5:4. Thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) and investigations of the corresponding structure and morphology change confirm that the nanobelts have low glass transition temperature and thermal stability. Optical diffuse reflectance spectrum indicates that the lead tellurite nanobelts have two optical gaps at ca. 3.72 eV and 4.12 eV. Photoluminescence (PL) spectrum and fluorescence imaging of the products exhibit a blue emission (round 480 nm)