Microcrystalline Bi2ZnB2O7-polymer composites with silver nanoparticles as materials for laser operated devices

A novel type of composite for optoelectronic which is operated by second harmonic generation in the Bi2ZnB2O7 crystallites (with sizes varying within 1–30 μm) and Ag nanoparticles (NP) embedded in PMMA polymer composites is proposed. The substantial influence of the Ag NP on the bicolor induced second harmonic generation was established. The phototreatment was performed by bicolor beams of nanosecond Nd:YAG laser (1,064/532 nm) at angles between the fundamental and photoinducing beams varying within the 19°–21° range. The studies of the corresponding dependences of the SHG during illumination by the two coherent beams at 1,064/532 nm showed a maximal enhancement of the output SHG for the Ag NP average sizes equal to about 40 nm. The role of the excited plasmons may be here crucial. Additionally the time shift between the fundamental and the doubled frequency beam maxima was found, which shows strong sensitivity to illumination. The established time shift is sensitive to the pumping power

Correlation Between Structure, Microstructure and Dielectric Properties of Bi7Fe3Ti3O21 Ceramics Obtained in Different Conditions

Multiferroic six-layer Aurivillius type Bi7Fe3Ti3O21 ceramics was obtained by conventional mixed oxides method. The final sintering process was taken in several different sintering times, which determined changes in properties of discussed ceramic material. The structure and dielectric properties of the material are reported. In order to examine the technological conditions on the crystal structure, XRD analysis was carried out. The microstructure, as well as the quantitative and qualitative analysis of the chemical composition were investigated by scanning electron microscope with an energy dispersion spectrometer. The main purpose of the paper is to present the effect of sintering time on the microstructure, crystallographic structure and dielectric properties of Bi7Fe3Ti3O21 ceramics

Visible and near-infrared up-conversion luminescence of KGd(WO4)(2) micro-crystals doped with Er3+, Tm3+, Ho3+ and Yb3+ ions.

KGd(WO4)(2) micro-crystals doped with Yb3+/Er3+/Tm3+, Yb3+/Er3+/Ho3+ and Yb3+/Tm3+/Ho3+ exhibit multicolor up-conversion luminescence in the VIS and NIR spectral ranges under 980 nm laser diode excitation. These rare earth-doped KGd(WO4)(2) micro-crystalline powders were synthesized using the modified Pechini method. XRD was used to confirm the monoclinic phase of these compounds. The SEM images analysis showed that the average size of the micro-crystals was smaller than 1 mm. The influence of the size and shape of micro-crystals on vibrational properties was investigated for the first time using the m-Raman spectroscopy. The obtained results suggest that the KGd(WO4)(2) powders doped with Yb3+/ Er3+/Tm3+, Yb3+/Er3+/Ho3+ and Yb3+/Tm3+/Ho3+ ions can be successfully used as new phosphors for the up-conversion based optoelectronic devices