Optical spectra and emission characteristics of terbium-doped potassium–lead double chloride crystals (KPb2Cl5:Tb3+)
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 5 D 3 and 5 D 4 levels are studied experimentally, the lifetimes of these levels are determined, and the dependences of the rates of nonradiative relaxation from the excited 7 F j (j = 0–5), 5 D 4, and 5 D 3 levels to lower-lying terbium levels are calculated. It is shown that the population of the 5 D 4 level in KPC:Tb3+ crystals occurs according to a cascade scheme, which leads to quenching of the 5 D 3 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 ΔE ji > 1000 cm–1 are W ji 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.
Unable to display preview. Download preview PDF.
- 1.L. I. Isaenko, A. P. Yelisseyev, A. M. Tkachuk, and S. E. Ivanova, in Mid-Infrared Coherent Sources and Application, Springer Ser. B: Phys. Biophys., Ed. by M. Ebrahimzadeh and I. Sorokina (Springer, Berlin, Dordrecht, 2008), p. 21.Google Scholar
- 5.M. C. Nostrand, R. H. Page, S. A. Payne, W. F. Krupke, P. G. Schunemann, and L. I. Isaenko, OSA Trends Opt. Photonics Ser. 34, 459 (2000).Google Scholar
- 8.S. R. Bowman, S. K. Searles, N. W. Jenkins, S. B. Qadri, E. F. Skelton, and J. Ganem, in Proceedings of the Conference on Lasers and Electro-Optics CLEO 2001, Baltimore, Maryland, May 8–10, 2001, CFD2, p. 557.Google Scholar
- 10.M. C. Nostrand, R. H. Page, S. A. Payne, W. F. Krupke, P. G. Schunemann, and L. I. Isaenko, OSA Trends Opt. Photonics Ser. 26, 441 (1999).Google Scholar
- 14.A. M. Tkachuk, S. E. Ivanova, L. I. Isaenko, A. P. Yelisseyev, and V. A. Pustovarov, OSA Trends Opt. Photonics Ser. 98, 69 (2005).Google Scholar
- 15.J. L. Doualan and R. Moncorge, Ann. Chim. Sci. Mater., No. 28, 5 (2003).Google Scholar
- 17.M. C. Nostrand, R. H. Page, S. A. Payne, W. F. Krupke, and L. I. Isaenko, in Proceedings of the of the Conference on Lasers and Electro-Optics CLEO-2000, San Francisco, May 7–12, 2000, p. 566.Google Scholar
- 25.A. G. Okhrimchuk, L. N. Butvina, E. M. Dianov, N. V. Lichkova, and V. N. Zavgorodnev, OSA Trends Opt. Photonics Ser. 83, 303 (2003).Google Scholar
- 29.A. M. Tkachuk, S. E. Ivanova, L. I. Isaenko, A. P. Yelisseyev, V. A. Pustovarov, M.-F. Joubert, Y. Guyot, and V. P. Gapontsev, OSA Trends Opt. Photonics Ser. 98, 69 (2005).Google Scholar