Article
Some interesting features of the Tb3+ magnetooptics in the paramagnetic garnets
Optical Materials
(2014)
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
Disciplines
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/