Spectroscopic properties of Sm3+-doped NaGd(MoO4)2 crystal for visible laser application

A NaGd(MoO4)2 crystal doped with 2 at.% Sm3+ was grown by the Czochralski method. Polarized absorption and fluorescence spectra of the crystal were measured at room temperature. Spectroscopic parameters, including absorption and emission cross sections, Judd-Ofelt intensity parameters, radiative transition rates, fluorescence branching ratios, and fluorescence lifetime of the 4G5/2 multiplet, were obtained and compared with other Sm3+-doped crystals. The main fluorescence band around 646 nm is related to the 4G5/2→6H9/2 transition, which has a branching ratio of 45.4% and peak emission cross sections of 1.73×10-21 and 3.13×10-21 cm2 for π and σ polarizations, respectively. The results indicate that the Sm3+:NaGd(MoO4)2 crystal may be a potential gain medium of red visible laser pumped directly by commercially available 405 nm laser diode.