Growth, Structure, and Evaluation of Laser Properties of LiYb(MoO₄)₂ Single Crystal

Because of the incongruent melting of LiYb(MoO 4 ) 2 compound at 912 °C, Li 2 MoO 4 and Li 2 Mo 2 O 7 fluxes have been used to nucleate single crystals of this compound. From the latter flux, crystals of about 1 cm 3 have been pulled by the top-seeded solution-growth method. Details on the preparation and growth procedures are provided. The Li concentration in the crystal has been assessed using 7 Li(p,α) 4 He nuclear reaction induced by protons. The [Yb]/[Li] molar composition ratio obtained in several samples is in the 1.01−1.05 range. This result compares well with the ratio [Yb]/[Li] = 1 expected from the above chemical formula, therefore nonextensive Li loss is experienced during the crystal growth. Polymorphic transformations to phases with symmetry lower than tetragonal have not been observed upon cooling. At room temperature the crystal structure shows the tetragonal space group I 4̄ (No. 82), with lattice parameters a = 5.1191 (9) Å and c = 11.109 (3) Å, V = 291.11(10) Å 3, and Z = 2. This implies a high ytterbium density, namely [Yb] = 6.87 × 10 21 cm - 3 . The optical absorption and photoluminescence properties are described in detail consistently with the anisotropic character of the tetragonal phase. The relative energies of the Yb 3+ Stark levels have been determined and the perspectives for applications as a laser material are evaluated.