Synthesis, characterization and nonlinear optical properties of silver/PVA nanocomposites

Silver/polyvinyl alcohol (PVA) nanocomposites are prepared via quick precipitation method, using hydrazine as a reducing agent. Preparing of silver/PVA nanocomposites by this method is done for the first time. The samples are characterized by Uv-Visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM). Nonlinear optical properties are carried out by Z-scan technique using a blue CW laser beam operated at wavelength 405 nm. It is shown that the synthesized samples have negative nonlinear refractive index and the magnitude is in the order of 10^-8. The nonlinear refractive index increases as amount of reducing agent increases

Photoluminescence and thermoluminescence properties of Li2O-Na2O-B2O3 glass

Influence of Nd3+ concentration on the optical and thermoluminescence (TL) properties of melt-annealed synthesized 10 Na2O: 20 Li2O: (70-x) B2O3: xNd2O3, where 0.1≤ x ≤0.7 (LNB) glasses are determined. The absence of sharp peaks in X-ray diffraction patterns confirms the amorphous nature of the prepared glasses. The photoluminescence spectra under 800 nm laser excitations at room temperature exhibit three prominent peaks centred at 538, 603 and 675 nm corresponding to the transitions of 4G7/2 → 4I9/2, [4G7/2 → 4I11/2, 4G5/2 → 4I9/2] and [4G7/2→ 4I13/2, 4G5/2 → 4I11/2], respectively. The TL glow curve exhibits a prominent peak (Tm) at 180°C. The best performance of the prepared glass was found at 0.5 mol% of Nd2O3. We achieved a good linearity of TL response against dose between 0.5 to 4.0 Gy. The calculated value of the effective atomic number, Zeff, is 7.55 which is nearly tissue equivalent (Zeff = 7.42). These promising features demonstrate the capability of the aforementioned glass to be used as a radiation dosimeter

Efficient, wide angle, structure tuned 1 x 3 photonic crystal power splitter at 1550 nm for triple play applications

We propose a wide angle, efficient and low loss 1 x 3 power splitter based on triangular lattice air holes silicon slab Photonic Crystal (PhC). Desired power splitting ratio was achieved by altering the structure at the junction area of the power splitter. Simulation results obtained using 2-D finite difference time domain method show that for TE polarization incident signal, the power is distributed almost equally with total normalized transmission of 99.74 and negligible reflection loss at the 1550 nm optical operating wavelength. In addition, the power splitter can operate at 1388 nm and 1470 nm optical wavelengths