Experimental and theoretical study of the crystal-field levels and hyperfine and electron-phonon interactions in LiYF_ {4}: Er^{3+} (original) (raw)
Related papers
Modeling of electron-vibrational 4fn–4fn−15d spectra in LiYF4:RE3+ crystals
Journal of Molecular Structure, 2007
In the present work, the low temperature absorption band shapes of the impurity Ce 3+ (4f-5d) and Lu 3+ (4f 14 -4f 13 5d) ions in LiYF 4 crystals have been simulated within adiabatic approximation on the basis of a derived microscopic model of electron-phonon interaction and phonon spectrum of the host lattice. Crystal field parameters and electron-phonon coupling constants were treated in the framework of the exchange charge model. Results of simulations of the spectral envelopes agree satisfactorily with the experimental data available from the literature.
Energy levels and line intensities ofPr3+in LiYF4
Physical Review B, 1979
High-resolution polarized absorption and fluorescence spectra of Pr'+ in LiYF4 were measured at temperatures between 10 and 300'K. Energy-level assignments were made assuming electric-dipole transition selection rules for S4 site symmetry. Forty-six energy levels of the 4f ground configuration were established, including 44 in the lowest nine multiplets. Crystal-field parameters were determined that gave a rms deviation of 15.8 cm ' between 41 of the experimental energy levels and calculated values. The parameters were B,o = 488.9, B40-1043, B44-1242, B"=-42, Re B64-1213, and Im B64-22.5 cm '. These parameters were used to obtain the remaining energy levels, yielding a complete energy-level scheme for the 4f configuration of Pr'+. The crystal-field parameters for Pr'+ in LiYF4 were compared to those for other ions in this host. A theoretical calculation of line intensities was performed in which the oddfold crystal-field parameters were obtained from a lattice sum. Line intensities were measured and compared with theory.
Cross-relaxation process between +3 rare-earth ions in LiYF4 crystals
Physical Review B, 1996
The cross-relaxation probability ͑sec Ϫ1 ͒ involving the 5 S 2 and 5 I 8 levels of holmium ions in LiYF 4 was investigated and its concentration dependence determined. By using a random distribution function of ions in the crystal, it was possible to determine the concentration dependence of the nonradiative probability for the ion-ion energy transfer by dipole-dipole, dipole-quadrupole, and quadrupole-quadrupole electric interactions. The applied model shows that the ion-ion cross-relaxation transfer between Ho 3ϩ ions in LiYF 4 crystals, cannot account for the experimental results. At a high concentration level of activators ͑Ͼ1%͒, the excited ion must interact with two neighbors of same specie competing with the single ion cross-relaxation transfer.
Physical Review B, 2010
High-resolution optical Fourier spectroscopy was used to study the energies and widths of the crystal-field (CF) levels, hyperfine and deformation level splittings, and isotopic effects in the LiYF 4 :Tm 3+ single crystals. We present the corrected sets of the CF levels and CF parameters for the Tm 3+ ion in LiYF 4 . The observed fine structure of spectral lines is shown to be caused by the hyperfine interaction, random lattice deformations, and isotopic disorder in the lithium sublattice. From a comparison between the observed and calculated fine structure we determine the characteristics of the random lattice deformations in highly diluted activated crystals and obtain an estimate of the fluorine displacements (~ 3⋅10 -5 nm) in the nearest surrounding of the mass defect at the lithium site.
Spectral signatures of hyperfine and isotopic effects and of Tm3+–Tm3+ pairs in LiYF4:Tm
Physics Letters A, 2008
We report on the high-resolution optical Fourier-transform spectroscopy of the LiYF 4 :Tm 3+ crystals. Splitting of several lines in the optical low-temperature polarized spectra was observed. We show that these splittings are caused by (i) the hyperfine interaction, (ii) the isotopic disorder in the lithium sublattice, and (iii) the interionic interaction between neighboring Tm ions. It is the first observation of the hyperfine splitting in the spectra of the Tm 3+ ions in crystals. From the experimentally measured hyperfine splitting we evaluate the magnetic field at the thulium nucleus and calculate the magnetic g-factors of the excited crystal-field levels.
Journal of the Optical Society of America B, 2000
Near-UV excited-state absorption spectra obtained with a pulsed pump-probe technique were recorded in LiYF 4 :Pr 3ϩ at 77 and at 8 K and revealed a detailed structure of the 4f 2 1 D 2 → 4f5d and 4f 2 (3 P 0 ϩ 1 I 6) → 4f5d optical transitions. These experimental results, together with those previously obtained at room temperature, are compared with the numerical predictions of a full calculation of the 4f5d sublevels and of the electric dipole transitions toward these sublevels from different states of the 4f 2 configuration. The agreement is good, provided that the four adjustable parameters of the theory are taken as B 20 (5d) ϭ 7290 cm Ϫ1 , B 40 (5d) ϭ Ϫ14 900 cm Ϫ1 , F 0 ϭ 60 557 cm Ϫ1 , and ͗r͘ fd ϭ 0.245 Å. The level structure of the 4f5d configuration of LiYF 4 :Pr 3ϩ is shown to be dominated, as expected, by the crystal field coupling of the 5d electron but also, to a noticeable extent, by the spin-orbit coupling of the 4f electron and the Coulomb repulsion of both electrons. The former of these two interactions is somewhat more efficient than the latter in the low-energy part of the 4f5d configuration, i.e., in the spectral region where the largest amount of experimental data is currently available.
Precise determination of the low-energy electronuclear Hamiltonian of LiY1−xHoxF4
Physical Review B
We use complementary optical spectroscopy methods to directly measure the lowest crystal-field energies of the rare-earth quantum magnet LiY1−xHoxF4, including their hyperfine splittings, with more than 10 times higher resolution than previous work. We are able to observe energy level splittings due to the 6 Li and 7 Li isotopes, as well as non-equidistantly spaced hyperfine transitions originating from dipolar and quadrupolar hyperfine interactions. We provide refined crystal field parameters and extract the dipolar and quadrupolar hyperfine constants AJ = 0.02703 ± 0.00003 cm −1 and B = 0.04 ± 0.01 cm −1 , respectively. Thereupon we determine all crystal-field energy levels and magnetic moments of the 5 I 8 ground state manifold, including the (non-linear) hyperfine corrections. The latter match the measurement-based estimates. The scale of the non-linear hyperfine corrections sets an upper bound for the inhomogeneous line widths that would still allow for unique addressing of a selected hyperfine transition e.g. for quantum information applications. Additionally, we establish the far-infrared, low-temperature refractive index of LiY1−xHoxF4.