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Some interesting features of the Tb3+ magnetooptics in the paramagnetic garnets
Optical Materials (2014)
  • Uygun V. Valiev, National University of Uzbekistan
  • John B. Gruber, University of Texas at San Antonio
  • Gary W Burdick, Andrews University
  • Anvar K Mukhammadiev, National University of Uzbekistan
  • Dejun Fu, Wuhan University
  • Vasiliy O Pelenovich, Wuhan University
Abstract
The spectra of the absorption, luminescence, magnetic circular dichroism (MCD) and magnetic circular polarization of luminescence (MCPL) in the terbium–yttrium gallium garnet Tb3+:Y3Ga5O12 (Tb:YGG) have been studied within the visible and near ultraviolet (UV) spectral range for temperatures T = 85 and 300 K. The MCD spectrum observed within the UV absorption band for Tb:YGG is associated with spin- and parity-allowed electric-dipole 4f → 5d transitions occurring between levels of the ground 7F6multiplet and the 7D state of the excited 4f(7)5d configuration of the Tb3+ ion. Analysis of the spectral and the temperature dependences of the magnetooptical and optical spectra has made it possible to identify magneto-optically-active 4f → 4f transitions occurring between Stark sublevels of the 5D4 and 7F5 multiplets in Tb3+:YGG. Quantum mechanical “mixing” of the three lowest energy Stark singlets in the excited 5D4 multiplet by an external magnetic field H leads to the change of the circularly polarized luminescence line intensities. The Zeeman effect in the UV absorption band 7F6 → 5L10of Tb3+:YGG at T = 85 K was also studied. The magnetic field dependence of the Zeeman splitting of some absorption lines is found to exhibit unusual behavior: as the magnetic field increases, the band splitting decreases rather than increases. A parameterized Hamiltonian defined to operate within the entire 4f(8) ground electronic configuration of Tb3+ was used to model the experimental Stark levels, their irreducible representations (irreps.) and wave functions. The crystal-field parameters were determined using a Monte-Carlo method in which nine independent crystal-field parameters, were given random initial values and optimized using standard least-squares fitting between calculated and experimental levels. The final fitting standard deviation between 101 calculated and experimental Stark levels is 16.7 cm−1.
Keywords
  • Luminescence,
  • Magnetic circular polarization of luminescence,
  • Magnetic circular dichroism,
  • terbium–yttrium garnet gallate
Publication Date
May, 2014
DOI
10.1016/j.optmat.2014.01.034
Citation Information
Uygun V. Valiev, John B. Gruber, Gary W Burdick, Anvar K Mukhammadiev, et al.. "Some interesting features of the Tb3+ magnetooptics in the paramagnetic garnets" Optical Materials Vol. 36 Iss. 7 (2014) p. 1101 - 1111
Available at: http://works.bepress.com/gary_burdick/61/