Optical spectroscopy of Pr³⁺in KGd(WO₄)₂single crystals

Abstract

The polarized optical absorption (OA) and photoluminescence of Pr3+ doped KGd(WO4)2 (KGW) single crystals have been measured at selected temperatures between 7 and 300 K. For the studied Pr concentrations, [Pr] = 0.03×1020-1.9×1020 cm-3, a unique site is observed. 74 energy levels were experimentally determined for this site and labelled with the appropriate A or B irreducible representations corresponding to the C2 symmetry of the Gd point site in KGW. The set was fitted to a Hamiltonian of adjustable parameters including free-ion as well as real Bqk and complex Sqk crystal-field parameters. A good simulation of the experimental crystal field energies was achieved with a root mean square deviation σ = 15.3 cm-1. Distortions in the oxygen bonds to Pr3+ are found to contribute to the broadening of some OA bands, particularly those related to the 1D2 multiplet. The OA edge is determined by the interconfigurational 4f→4f15d1 Pr3+ transition peaking at 34 200 cm-1. From the average 300 K OA cross sections the radiative lifetimes of the Pr3+ multiplets have been calculated considering the standard and modified Judd-Ofelt (JO) theories. A better agreement with the experimental results is obtained by the standard theory: the average JO parameters obtained at ω̄2 = 12.0×10-20 cm2, ω̄4 = 8.15×10-20 cm2 and ω̄6 = 2.64×10-20 cm2. Electrons excited to the 3P0 multiplet decay very efficiently to the 1D2 multiplet even at 15 K. In samples with [Pr]⩾0.3×1020 cm-3 the excitation of the 1D2 multiplet decays non-radiatively by an electric dipole-dipole transfer between Pr neighbours.

Laser crystals and ceramics: recent advances

“…Laser action can also be achieved at this intermanifold transition using the direct cascade 3 P 0 → 1 G 4 → 3 F 4 scheme [18]. New properties of Pr 3+ activator ions have been discovered [182,279].…”

On the influence of dopant ions on blue emission in kgw crystal excited by infrared laser radiation

“…It was hypothesized that it arose through an upconversion mechanism at Nd 3+ ions that resulted from absorption from excited state 4 F 5/2 into state 2 K 15/2 + 2 D 3/2 with an emissive transition into ground state 4 I 9/2 . However, the luminescence branching ratios from high-lying Nd 3+ multiplets have not been reported.…”

The EPR of monoclinic KY(WO4)2 single crystal doped with Sm3+ ion

“…[1]. The α-KRE(WO 4 ) 2 tungstate also has sufficiently strong optical nonlinearity to be used in devices working on the basis of stimulated Raman scattering [2][3][4][5][6].…”