Anisotropy in spectroscopic and laser properties of Yb:Sr_3La_2(BO_3)_4 disordered crystal

Abstract

We report, for the first time to our knowledge, on the polarized absorption and emission spectra and efficient laser action of the Yb:Sr3La2(BO3)4 disordered crystal. The strongest absorption and emission occur at about 977 nm for polarization direction parallel to the crystallographic b axis, with the peak absorption and emission cross-sections amounting, respectively, to 1.95 × 10−20 and 2.45 × 10−20 cm2. Efficient continuous-wave laser action is demonstrated with a-, b-, and c-cut crystal samples longitudinally pumped by a 976-nm diode laser, producing an output power of up to 8.2 W with an optical-to-optical efficiency of 32% with respect to incident pump power. Depending on the output coupling utilized, the laser action could exhibit a transition from single-polarization oscillation to dual-orthogonal-polarization oscillation at a certain pump level.