Crystal growth,structure and optical properties of Pr^(3+)-doped yttria-stabilized zirconia single crystals

The development of blue semiconductor light-emitting diodes(LEDs)has produced potential applications for Prdoped materials that can absorb blue light,especially crystals,and we now report structure and optical properties for high-quality Pr-doped single crystals of yttria-stabilized zirconia(YSZ)grown by the optical floating zone(FZ)method.X-ray diffraction(XRD)and Raman spectroscopy showed that all of the single crystal samples were in the cubic phase,whereas the corresponding ceramic samples contained a mixture of monoclinic and cubic phases.X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)spectroscopy showed that Pr was present as the Pr^(3+)ion in ceramic rods and single crystals after heating to high temperatures.The absorption and photoluminescence excitation(PLE)spectra of the Pr-doped YSZ crystals measured at room temperature showed strong absorption of blue light,while their photoluminescence(PL)spectra showed five emission peaks at 565 nm,588 nm,614 nm,638 nm,and 716 nm under450 nm excitation.The optimum luminescence properties were obtained with the crystal prepared using 0.15 mol%Pr_(6)O_(11),and those with higher concentrations showed evidence of quenching of the luminescence properties.In addition,the color purity of Pr-doped YSZ single crystal reached 98.9%in the orange–red region.

Performance Enhancement of Praseodymium Doped Fiber Amplifiers

In this paper,we report a simulation study on the performance enhancement of Praseodymium doped silica fiber amplifiers(PDFAs)in O-band(1270-1350 nm)in terms of small signal gain,power conversion efficiency(PCE),and output optical power by employing bidirectional pumping.The PDFA performance is examined by optimizing the length of Praseodymium doped silica fiber(PDF),its mode-field diameter(MFD)and the concentration of Pr^(3+).A small-signal peak gain of 56.4 dB,power conversion efficiency(PCE)of 47%,and output optical power of around 1.6 W(32 dBm)is observed at optimized parameters for input signal wavelength of 1310 nm.Minimum noise figure(NF)of 4.1 dB is observed at input signal wavelength of 1310 nm.Moreover,the effect of varying the pump wavelength and pump power on output optical power of the amplifier and amplified spontaneous emission(ASE)noise is also investigated,respectively.Finally,the impact of ion-ion interaction(up-conversion effect)on small-signal gain of the amplifier is also studied by considering different values of up-conversion coefficient.

Prediction of aggregation behavior of submicron-sized particles of praseodymium-doped zirconium silicate in aqueous suspension by population balance model

The aggregation behavior of submicron-sized particles of praseodymium-doped zirconium silicate, a ceramic pigment, in aqueous suspension was predicted by a modified population balance model, In the model, the collision frequencies were selected to describe evolution of the particle size distribution of the suspension. The collision efficiency was estimated as a function of interaction potential between particles based on Derjaguin-Landau-Verwey-Overbeek theory. The population balance model was modified to predict the stable state of the aggregation by introducing the volume mean size of aggregate to stability ratio. In addition, aggregation of the particles in aqueous suspension in the presence of sodium dodecyl benzene sulfonate or potassium chloride was experimentally investigated. The predicted data （i.e., the final aggregate size, aggregation rate, and particle size distribution） were similar to the experimentalresults.