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231 results on '"Ryba-Romanowski, Witold"'

4. Spectroscopic and Thermographic Qualities of Praseodymium-Doped Oxyfluorotellurite Glasses.

Author

Klimesz, Barbara, Ryba-Romanowski, Witold, and Lisiecki, Radosław

Abstract

The thermal stability of oxyfluorotellurite glass systems, (65-x)TeO2 -20ZnF2 -12PbO-3Nb2O5 - xPr2O3 , doped with praseodymium was examined. The different concentrations of praseodymium oxide (x = 0.5 and 2 mol%) were applied to verify the thermal, optical and luminescence properties of the materials under study. The relatively high values of the Dietzel (∆T) and Saad–Poulain (S or H′ ) thermal stability factors determined using a differential thermal analysis (DTA) indicate the good thermal stability of the glass matrix, which gradually improves with the content of the active dopant. The temperature dependence of optical spectra in the temperature range 300–675 K for the VIS–NIR region was investigated. The involved Pr3+ optical transition intensities and relaxation dynamic of the praseodymium luminescent level were determined. The ultrashort femtosecond pulses were utilized to examine a dynamic relaxation of the praseodymium luminescent levels. Although the measured emission of the Pr3+ active ions in the studied glass encompasses the quite broad spectral region, the observed luminescence may only be attributed to 3PJ excited states. As a result, the observed decrease in the experimental lifetime for the 3P0 level along with the increasing activator content was identified as an intensification of the Pr–Pr interplay and the associated self-quenching process. The maximum relative sensitivities (Sr) estimated over a relatively wide temperature range are ~0.46% K−1 (at 300 K) for FIR (I530/I497) and 0.20% K−1 (at 600 K) for FIR (I630/I497), which seems to confirm the possibility of using investigated glasses in optical temperature sensors. [ABSTRACT FROM AUTHOR]

Published
2024
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45. Exploring Structure-Sensitive Factors Relevant to Cryogenic Laser Operation in Oxide Crystals Doped with Er 3+ Ions.

Author

Ryba-Romanowski, Witold, Lisiecki, Radoslaw, Komar, Jaroslaw, Macalik, Boguslaw, and Berkowski, Marek

Subjects
*OPTICAL pumping, *CRYSTALS, *LIGHT absorption, *LASERS, *ABSORPTION spectra, *LUTETIUM compounds, *GADOLINIUM
Abstract

Crystals of Gd3Al2.5Ga2.5O12:Er3+, (Lu0.3Gd0.7)2SiO5:Er3+ and LiNbO3:Er3+ compounds differing in origin and the nature of their inherent structural disorder were crystalized. Optical absorption and luminescence spectra for transitions between the 4I15/2 and the 4I13/2 multiplets of Er3+ ions for the crystal samples were recorded versus temperatures in the region of 80–300 K. Gathered data were analyzed thoroughly providing the in-depth knowledge of the effects of temperature on intensities, wavelengths and bandwidths of Er3+ transitions. The information acquired together with the knowledge of significant structural dissimilarities of the host crystals chosen made it possible to propose an interpretation of the impact of a structural disorder in Er3+-doped crystals on their spectroscopic properties, and to determine their lasing ability at cryogenic temperatures upon resonant (in-band) optical pumping. [ABSTRACT FROM AUTHOR]

Published
2023
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