Monoclinic Tm:MgWO4crystal: Crystal-field analysis

Identifier:  imarina:3934047

Handle: https://hdl.handle.net/20.500.11797/imarina3934047

Authors:  Loiko, Pavel; Wang, Yicheng; Maria Serres, Josep; Mateos, Xavier; Aguilo, Magdalena; Diaz, Francesc; Zhang, Lizhen; Lin, Zhoubin; Lin, Haifeng; Zhang, Ge; Dunina, Elena; Kornienko, Alexey; Fomicheva, Liudmila; Petrov, Valentin; Chen, Weidong

Abstract:
© 2018 Elsevier B.V. Tm3+-doped monoclinic magnesium monotungstate (MgWO4) is a promising material for lasers emitting at above 2 μm. Stark splitting of3H6to1G4Tm3+multiplets in MgWO4is determined using low-temperature spectroscopy, calculated within crystal-field theory modified for the case of an intermediate configuration interaction (ICI) and analyzed in terms of the barycenter plot. Tm3+:MgWO4features a large Stark splitting of the ground-state (3H6), 633 cm−1, and high transition cross-sections for polarized light due to its low-symmetry structure. A unique feature of Tm3+:MgWO4to provide a naturally polarized emission at >2 μm, as well as its suitability for broadly tunable and mode-locked lasers in this spectral range are argued. The first tunable and vibronic Tm3+:MgWO4lasers are demonstrated, yielding a continuous tuning from 1897 to 2062 nm in the former case. A vibronic laser operated at even longer wavelengths up to 2093 nm due to electron-phonon coupling with low-energy phonons of the crystalline host. Moreover, the optical indicatrix axes of high-refractive-index biaxial MgWO4are assigned.