Инд. авторы:	Tkachuk A.M., Ivanova S.E., Mirzaeva A.A., Isaenko L.I.
Заглавие:	Optical spectra and emission characteristics of terbium-doped potassium–lead double chloride crystals (KPb2Cl5:Tb3+)
Библ. ссылка:	Tkachuk A.M., Ivanova S.E., Mirzaeva A.A., Isaenko L.I. Optical spectra and emission characteristics of terbium-doped potassium–lead double chloride crystals (KPb2Cl5:Tb3+) // Optics and Spectroscopy. - 2017. - Vol.122. - Iss. 5. - P.735-748. - ISSN 0030-400X. - EISSN 1562-6911.
Внешние системы:	DOI: 10.1134/S0030400X17050198; SCOPUS: 2-s2.0-85019674605; WoS: 000402082700008;
Реферат:	eng: Optical transitions in KPb2Cl5:Tb3+ crystals are studied experimentally and theoretically. The absorption cross-section spectra are plotted and the oscillator strengths of transitions from the ground terbium state to excited multiplets are determined. Intensity parameters Ωt for KPC:Tb3+ are determined by the Judd–Ofelt method to be Ω2 = 2.70 × 10–20 cm2, Ω4 = 7.0 × 10–20 cm2, and Ω6 = 0.72 × 10–20 cm2. These values were used to calculate such characteristics of spontaneous radiative transitions as oscillator strengths, probabilities of radiative transitions, and radiative lifetimes. The emission spectra of KPb2Cl5:Tb3+ crystals upon UV excitation and the decay kinetics of luminescence from the excited 5D3 and 5D4 levels are studied experimentally, the lifetimes of these levels are determined, and the dependences of the rates of nonradiative relaxation from the excited 7Fj (j = 0–5), 5D4, and 5D3 levels to lower-lying terbium levels are calculated. It is shown that the population of the 5D4 level in KPC:Tb3+ crystals occurs according to a cascade scheme, which leads to quenching of the 5D3 level. The calculated data agree well with the known experimental rates of multiphonon nonradiative transitions for Dy:KPC, Nd:KPC, Er:KPC, Tb:KPB, and Nd:KPB crystals. It is shown that transitions in the near-IR (3–6 μm) region in double halide crystals (MPb2Hal5) are almost unquenched and the rates of nonradiative relaxation of excited levels spaced by energy gaps ΔEji > 1000 cm–1 are Wji NR < 103s–1. This circumstance suggests that it is possible to obtain stimulated emission in KPb2Cl5:RE3+ crystals in the IR spectral region up to 6 μm. © 2017, Pleiades Publishing, Ltd.
Ключевые слова:	Radiative transitions; Oscillator strengths; Non-radiative transitions; Non-radiative relaxation; IR spectral regions; Intensity parameters; Emission characteristics; Absorption cross sections; Terbium; Relaxation oscillators; Potassium alloys; Fighter aircraft; Emission spectroscopy; Excited states;
Издано:	2017
Физ. характеристика:	с.735-748