D. Kasprowicz

Optical properties of KGd(WO4)2 single crystals studied by Brillouin spectroscopy

The analysis some of the acoustic phonons propagating in pure and Ho3+-doped KGd(WO4)2 single crystals in the GHz frequency range by Brillouin scattering method has been presented. For investigated crystals the velocities of the longitudinal and transverse acoustic phonons [100], [010], [001], [101], [101] and [110] have been determined. Moreover, the value of elastic constants C22, C44 and C66 of pure and Ho3+-doped KGd(WO4)2 single crystals have been estimated. It was revealed that the presence of the Ho3+-ions in KGd(WO4)2 crystals, for the used doping concentration 1 at% and 8 at%, does not influence their elastic properties. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Band Structure of SrLaGaO3+δ and SrLaAlO3+δ

The influence of oxygen on the electronic structure of strontium lanthanum gallate SrLaGaO 3 δ (SLG) and strontium lanthanum alluminate SrLaAlO 3+δ (SLA) crystals is presented. The band structures of SLA and SLG crystals were calculated by ab-initio tight-binding linear muffin tin orbital (TB LMTO) method within an atomic sphere approximation. The self-consistent band calculations indicate that SrLaGaO 4 , SrLaAlO 4 and SrLaAlO 3 are semiconductors, while SrLaGaO 3 , SrLaGaO 3+δ and SrLaAlO 3+δ for δ = 2 and 3 have the metallic character.

Anisotropy of the Elastooptic Properties of SLA and SLG Crystals Studied by Brillouin Scattering

The influence of annealing of SrLaAlO 4 (SLA) and SrLaGaO 4 (SLG) crystals on their elastooptic properties has been reported. The results obtained are discussed in terms of the nature of the oxygen point defects which might be created in the crystals during the growth process.

Optical Properties of Bismuth Triborate (BIBO) Single Crystals

We present a study of the nonlinear optical and elasto-optic properties of BiB 3 O 6 (BIBO) crystal. The estimated values of the nonlinear optical coefficients d ij are compared with the previously published values. Efficiency of the phase matched SHG and optical damage threshold for Q-switched Nd-YAG laser radiation are reported as well. The elastooptic constants p ij corresponding to the acoustic phonons propagating in q = [100], q = [010], q = [001], q = [110], q = [101] directions were estimated using Brillouin scattering method.

Influence of Growth Conditions on the Elastic Properties of SrLaAlO4 and SrLaGaO4 Crystals Studied by Brillouin Scattering Method

Study of the elastic properties of SrLaAlO 4 (SLA) and SrLaGaO 4 (SLG) crystals has been reported. The absorption of the yellow and green SLA and SLG crystals in the visible range was also investigated. The results obtained are discussed in terms of the nature of the oxygen point defects, which might be created in the crystals during the growth process.

Raman scattering study of butane-1,4-diol dimethacrylate

A study of the Raman light scattering in butane-1,4-diol dimethacrylate was performed in the temperature range 12–37 °C. It was found that the temperature dependence of the relative intensities of the bands deriving from the CC, CO and C—H bonds reveals a discontinuity at ca. 21–24 °C which coincides with the previously observed temperature discontinuity of the optical Kerr effect and Brillouin light scattering. The result is discussed in terms of changes in molecular interactions and arrangement in the liquid compound investigated.

Up-conversion luminescence of rare earth-doped KGd(WO4)2 phosphors for tunable multicolour light generation

A series of novel KGd(WO4)2 crystalline powders doped with Yb3+/Tm3+, Yb3+/Er3+ and Yb3+/Ho3+ were synthesized using a modified Pechini method. The monoclinic structure of these compounds was confirmed by XRD. The luminescence properties were investigated by measuring up-conversion luminescence spectra and decay curves. KGd(WO4)2 crystalline powders doped with Yb3+/Tm3+, Yb3+/Er3+ and Yb3+/Ho3+ exhibit effective multicolour up-conversion luminescence in the VIS and NIR spectral ranges under 980 nm excitation. The vibrational properties of the materials were investigated using μ-Raman spectroscopy. The assistance of low energy phonons of the KGd(WO4)2 matrix in the energy transfer processes between the excited manifolds of the Yb3+, Er3+, Tm3+ and/or Ho3+ ions during the up-conversion process was discussed. These results indicate that KGd(WO4)2 powders doped with selected Tm3+, Er3+, Ho3+ and Yb3+ ions may be potentially used as single-component multicolour or white emission phosphors.

Bi-functional Bi2ZnOB2O6 single crystals doped with Nd3+ or Pr3+: luminescence and µ-Raman investigations

The investigated Bi2ZnOB2O6 nonlinear optical single crystals doped with Nd3+ or Pr3+ ions were grown by the Kyropoulos method. Bi2ZnOB2O6 single crystals doped with selected RE3+ ions are characterized by high values of nonlinear optical coefficients as well as the effective luminescence of excited RE3+ ions, which make this system a unique candidate for laser converters. The vibrational properties of Bi2ZnOB2O6:Nd3+ and Bi2ZnOB2O6:Pr3+ single crystals were investigated with the use of μ-Raman spectroscopy. The strong emission of Bi2ZnOB2O6:Nd3+ single crystals with maximum at about 1062 nm (4F3/2→4 I11/2 transition) was detected under the excitation at 514 nm. Emission spectrum of Bi2ZnOB2O6:Pr3+ show enhancement of emission with maxima at about 1350 and 1470 nm ( 1D2→3H4 and 1G2→3H5 transition). The effective luminescence of excited Nd3+ or Pr3+ ions in Bi2ZnOB2O6 single crystals as well as excellent nonlinear optical properties of Bi2ZnOB2O6 host suggest that the investigated system can be very useful as a bifunctional crystals for new integrated optical systems such as self-frequency doubling lasers.

Up-conversion luminescence and µ-Raman investigations of KGd(WO 4 ) 2 crystalline powders doped with rare earth ions

KGd(WO₄)₂ /(KGW) micro-crystalline powders, doped with selected rare earth (RE) ions, namely Ho³⁺, Er³⁺, Tm³⁺, Tb³⁺ and/or Yb³⁺ ions, were synthesized using modified Pechini method. RE doped KGW micro-crystalline powders exhibit multicolor up-conversion luminescence in the VIS and NIR spectral ranges under 975 nm laser diode excitation. The spectroscopic properties of KGW:RE³⁺ were investigated using the μ-Raman spectroscopy and optical spectroscopy methods. The investigated KGW:RE³⁺ powders are very promising materials as new generation energy converters with significant potential applications in novel optical devices.

Temperature study of Tb 3+ , Yb 3+ and Tm 3+ tridoped KGd(WO 4 ) 2 crystals by raman spectroscopy

In the last few years a significant interest has been motivated in the development of novel rare earth doped solid state laser materials allowing infrared to visible frequency up-conversion has been motivated by their potential applications in optoelectronic devices [1,2]. The lanthanide doubly doped KGd(WO 4 ) 2 host crystals have been recognized as one of the most efficient up-conversion materials. In the present work the vibrational properties of the Tb3+, Yb3+ and Tm3+ tridoped KGd(WO 4 ) 2 crystals have been studied by Raman spectroscopy. The vibrational studies of the KGd(WO 4 ) 2 host lattice are particularly important due to its role in transfer of excitation energy between Tb3+, Yb3+ and Tm3+ ions in energy conversion process.