A5081598635- Luminescence Properties of Advanced Materials
- Radiation Detection and Scintillator Technologies
- Solid-state spectroscopy and crystallography
- Perovskite Materials and Applications
- Atomic and Subatomic Physics Research
- Optical properties and cooling technologies in crystalline materials
- Advanced Chemical Physics Studies
- Glass properties and applications
- Terahertz technology and applications
- Photorefractive and Nonlinear Optics
- Solid State Laser Technologies
- Semiconductor Quantum Structures and Devices
- Nuclear materials and radiation effects
- Quantum Dots Synthesis And Properties
- Ga2O3 and related materials
- Lanthanide and Transition Metal Complexes
- Atomic and Molecular Physics
- Quantum optics and atomic interactions
- Inorganic Fluorides and Related Compounds
- Inorganic Chemistry and Materials
- Advanced Semiconductor Detectors and Materials
- Optical and Acousto-Optic Technologies
- Advanced Condensed Matter Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Spectroscopy and Quantum Chemical Studies
University of Tartu
2015-2024
Czech Academy of Sciences, Institute of Physics
1972-2012
In-Q-Tel
1999
Universidad de Sonora
1996
Estonian Academy of Sciences
1982-1995
Institute of Physics
1970-1973
Bi-doped compounds recently became the subject of an extensive research due to their possible applications as scintillator and phosphor materials. The oxides co-doped with Bi3+ trivalent rare-earth ions were proposed prospective phosphors for white light-emitting diodes quantum cutting down-converting materials applicable enhancement silicon solar cells. Luminescence characteristics different Bi3+-doped found be strongly ascribed electronic transitions from excited levels a ion its ground...
Emission and excitation spectra decay kinetics are studied for the luminescence of undoped LuAG YAG crystals. Two emission bands located at 4.8 eV 3.95 in 4.9 3.65 LuAG, excited Eexc>6.5 energy region. They both characterized by a relatively slow (µs) time, ascribed to transitions from two different configurations an exciton localized near antisite defect (Y3+Al or Lu3+Al). The corresponding band, peaking 6.9 7.2 is perturbed defect. Besides emissions, weak fast (ns) self-trapped exciton,...
The luminescence of the alkali halides doped with ns 2 ions is studied in a wide temperature region by methods time-resolved polarization spectroscopy use magnetic and electric fields. It established that structure properties relaxed excited states (RES) all centers investigated may be adequately described terms theory which considers strong Jahn-Teller effect as main interaction RES. Very interesting effects processes are also observed, caused some weaker interactions: spin-orbit, hyperfine...
Abstract Partially polarized luminescence is observed for Ga + , In and Tl centres in alkali halides of CsCl‐type structure at liquid nitrogen temperature. The symmetry excited established to be tetragonal the most crystals investigated. CsI:Tl trigonal. possible causes low are discussed. interaction optical electrons activator with vibrations lattice may main cause halides. partial covalent bond between thallium some surrounding iodine ions seems essential crystals.
Four emission bands, all belonging to the main thallium centres, have been detected in CsI:Tl, and their spectral, polarization kinetic characteristics studied at 0.35-320 K. A new model is proposed for excited states responsible luminescence of thallium-doped caesium iodide. In this model, centre considered as a cluster consisting Tl+ ion least 12 I- 11 Cs+ ions. Two weak ultraviolet bands CsI:Tl (3.31 3.09 eV) are ascribed electronic transitions from trigonal tetragonal Jahn-Teller minima...
Abstract Luminescence, energy transfer and defects creation processes were studied at 4.2–300 K for Ce 3+ ‐doped Lu 3 Al 5 O 12 crystals under excitation in the 2.5–11.5 eV range. The results obtained compared with characteristics of Y :Ce crystals. It was concluded that both systems efficiency from host lattice to impurity ion can be noticeably increased by decrease concentration responsible their intrinsic luminescence. origin optically created possible mechanisms formation are discussed....
Abstract Single crystalline films (SCFs) of Y 3 Al 5 O 12 :Bi and Lu with different Bi 3+ contents are studied at 1.7–300 K by the time‐resolved luminescence spectroscopy methods under excitation in 2.4–20 eV energy range. The ultraviolet (UV) emission these SCFs is shown to arise from radiative decay metastable minima triplet relaxed excited state (RES) a single centre, which related P 0 1 levels free ion, respectively. At T < 80 K, only observed resulting appearance low‐energy component...
Abstract Undoped single crystals of Lu 3 Al 5 O 12 annealed in the reduced atmosphere or additively colored vapors were studied at 4.2–400 K by time‐resolved spectroscopy methods. The 3.15 eV emission, excited 3.4, 5.3, and 6.1 absorption bands having a decay time 3.14 ns 10 K, was ascribed to F + ‐type centers. It suggested that these centers consist an oxygen vacancy with one trapped electron which is perturbed neighboring antisite defect (Lu ) impurity ion 3+ site. small Stokes shift...
Single-crystalline films of Lu(3)Al(5)O(12):Bi, prepared by the liquid phase epitaxy method from melt-solution based on Bi(2)O(3) flux, have been studied at 4.2-400 K time-resolved luminescence spectroscopy methods. Their emission spectra consist two types bands with strongly different characteristics. The ultraviolet band consists components, arising electronic transitions which correspond to [Formula: see text] and in a free Bi(3+) ion. At low temperatures, mainly lower-energy component...
We studied the processes of hole and electron trapping in yttrium orthosilicate ${\mathrm{Y}}_{2}{\mathrm{SiO}}_{5}$ single crystals using continuous wave pulse spin resonance methods. show that holes created by x-ray irradiation at low temperatures ($T<80$ K) are preferably self-trapped Si-unbound oxygen ions form $\mathrm{O}{}^{\ensuremath{-}}$ centers. Under higher (200--290 K), trapped vicinity perturbing defects such as vacancies impurity forming a variety centers with thermal stability...
Abstract Steady‐state emission and excitation spectra luminescence decay kinetics were studied at 80–300 K under in the 2.5–6.0 eV energy range for undoped Ce 3+ ‐doped aluminium garnet (Lu 3 Al 5 O 12 , Y ) perovskite (LuAlO YAlO single crystalline films (SCF) grown by Liquid Phase Epitaxy method from PbO‐based flux. The aim of work was to identify spectral bands, arising lead‐induced centers different types, clarify their influence on scintillation characteristics centers. It found that...