Growth, structure, and polarized spectroscopy of monoclinic Er 3+ :MgWO 4 crystal
Résumé
We report on the growth, structure, and polarized spectroscopy of a novel promising laser crystal, erbium-doped magnesium monotungstate, Er 3+ :MgWO 4 . 1.01 t.% Er 3+ :MgWO 4 was grown by the Top-Seeded Solution Growth method using Na 2 WO 4 as a solvent. The crystal structure was refined by the Rietveld method. Er 3+ :MgWO 4 belongs to the monoclinic class (sp. gr. P 2/ c , wolframite-type structure, lattice parameters: a = 4.6939(6) Å, b = 5.6747(4) Å, c = 4.9316(6) Å and β = 90.7858(4) Å. The transition intensities for Er 3+ ions were determined using the Judd-Ofelt theory accounting for an intermediate configuration interaction (ICI). Er 3+ ions in MgWO 4 exhibit intense, strongly polarized and broad absorption and emission bands owing to their accommodation in distorted low-symmetry sites (C 2 ). The stimulated-emission cross-section for the 4 I 13/2 → 4 I 15/2 transition is 0.31×10 −20 cm 2 at 1637 nm (light polarization: E || b ). The radiative lifetime of the 4 I 13/2 state is 4.85 ± 0.05 ms. The multiphonon non-radiative relaxation for Er 3+ excited multiplets is quantified. Er 3+ ions in MgWO 4 feature large Stark splitting of the ground-state, Δ E ( 4 I 15/2 ) = 435 cm -1 . Er 3+ :MgWO 4 is attractive for low-threshold lasers at ∼1.64 µm.
Domaines
Optique [physics.optics]
Origine : Fichiers produits par l'(les) auteur(s)