Tadeusz Lukasiewicz

Publications (2)5.94 Total impact

• Article: Effect of temperature on spectroscopic features relevant to laser performance of YVO4:Er(3+) and GdVO4:Er(3+) crystals.

  Radosław Lisiecki, Piotr Solarz, Grazyna Dominiak-Dzik, Witold Ryba-Romanowski, Tadeusz Lukasiewicz
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  ABSTRACT: Optical spectra and luminescence decay curves were measured for erbium-doped YVO(4) and GdVO(4) single crystals as a function of temperature in the 300 K-670 K temperature region. In spite of structural similarity the two systems studied display significantly different transition intensities and nonradiative relaxation rates. It was found in particular that the intensity of parasitic upconverted emission excited at 978 nm depends weakly on temperature for YVO(4):Er(3+), whereas it decreases monotonously with increasing temperature for GdVO(4):Er(3+) and becomes negligibly small at 670 K. It was concluded that GdVO(4):Er(3+) may be a promising laser active material operating at high thermal loading conditions encountered in high-power diode-pumped IR lasers.
  Optics Letters 11/2009; 34(21):3271-3. · 3.40 Impact Factor
• Article: High-pressure crystallography of rhombohedral PrAlO(3) perovskite.

  Jing Zhao, Nancy L Ross, Ross J Angel, Michael A Carpenter, Christopher J Howard, Dorota A Pawlak, Tadeusz Lukasiewicz
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  ABSTRACT: The evolution of the crystal structure of rhombohedral PrAlO(3) perovskite with pressure has been investigated by single-crystal x-ray diffraction and Raman scattering experiments. The structural evolution as indicated by lattice strains, octahedral tilts, and the distortions of the octahedral AlO(6) and polyhedral PrO(12) groups with increasing pressure, is controlled by the relative compressibilities of the AlO(6) octahedra and the PrO(12) site. Because the AlO(6) octahedra are more compressible than the PrO(12) sites, up to 7.4 GPa the structure evolves towards the high-symmetry cubic phase like any other rhombohedral perovskite. The variation of volume of the rhombohedral phase with pressure can be represented by a third-order Birch-Murnaghan equation of state with bulk modulus K(0) = 193.0(1.2) GPa and K' = 6.6(4). Above 7.4 GPa the evolution towards a cubic phase is interrupted by a phase transition. Observations are consistent with the assignment of Imma symmetry to the high-pressure phase. Comparison with the low-temperature [Formula: see text] to Imma transition confirms that electronic interactions stabilize the Imma phase.
  Journal of Physics Condensed Matter 06/2009; 21(23):235403. · 2.55 Impact Factor