Fabrication and spectroscopic broadening properties for 1.5 microm amplification of Er(3+)-doped BaF2 nanoparticles.

We show the potential application of Er(3+)-doped BaF2 nanoparticles prepared from microemulsion technology for 1.5 microm amplification in telecommunication. Nanoparticles with different sizes of about 8, 10, and 20.5 nm were prepared. The XRD patterns showed the excursion of diffraction peaks. When the particle size is smaller or the diffraction angle is larger, this kind of excursion will be more serious. The emission bands of Er3+ at 1.54 microm for the three particle sizes at were as follows: 8 nm particles--145 nm, 10 nm particles--124 nm, and 20.5 nm particles--82 nm (full width at half maximum, FWHM), or 173, 153, 97 nm (deltalambda(eff)), respectively. In all the three cases, the emission spectra were flat from 1.53 to 1.56 microm.

Spontaneous ring-like self-assembly of BaF2 nanoparticles.

Self-assembly of BaF2 nanoparticles was described. BaF2 nanoparticles were prepared by microemulsion technology. The self-assembly of the particles is spontaneous without coating reagent on the surface or external force being applied during the procedure of sample preparation. XRD examination and ICP data showed the phase purity of the final product; FTIR spectroscopy confirmed that there was no organic species leaved in the product. By depositing one drop of colloid solution containing BaF2 particles on the TEM grid directly, we can get the ring-like self-assembly with larger particles dispersing peripherally to form a ring and smaller particles inside this ring forming circles.

[Concentration dependence of luminescence under different excitation wavelength in Y2O2S:Sm3+ phosphor].

The concentration dependence of luminescence under different excitations in Y2O2S:Sm3+ phosphor has been studied. The optimum activator concentration was found to be a function of the number of excited activator ions as well as the excitation wavelength. The concentration dependence curve of Y2O2S:Sm3+ phosphor under 413 nm excitation was different from the curve obtained with 263 nm excitation. For excitation radiation having longer wavelength (413 nm), the concentration quenching of Y2O2S:Sm3+ phosphor occurred at about 2%, which is ten times the result with shorter wavelength (263 nm) excitation (-0.2%). Fitting the concentration dependence curve and the result shows that the cross-relaxation caused by the dipole-quadrupole interaction of neighboring Sm3+ ions results in the concentration quenching.