Optical properties of Cr3+:NaAl(WO4)2 crystals, a new candidate for broadband laser applications

Single crystals of the recently synthesized double tungstate NaAl(WO4)2-doped with Cr3+ were grown with the use of the top seeded solution growth technique by slow cooling of nonstoichiometric solutions. Measurements of the optical characteristics of samples with chromium concentrations in the range 1.4 × 1019–1.3 × 1020 atoms/cm3 were carried out. Absorption and luminescence spectra of Cr3+:NaAl(WO4)2 were obtained at temperatures between 6 and 300 K and the temperature dependence of the Cr3+ luminescence lifetime was established. The Dq/B value found indicates that Cr3+:NaAl(WO4)2 belongs to the high-field site crystals. The results show that the new crystal is a good candidate for broadband laser applications.